Theoretical derivation of a bias-reduced expression for the extrapolation of the species accumulation curve and the associated estimation of total species richness.

16 pagesInternational audienceUnder-sampling becomes the current situation for an increasing part of biodiversity surveys, as more and more speciose assemblages and increasingly complex taxonomic groups are progressively addressed. Accordingly, (i) extrapolating the Species Accumulation Curve and (ii) estimating the total species richness of partially-sampled species assemblages (or taxonomic-groups) both become major issues for many naturalists nowadays. Numerous different solutions have been proposed to address these issues. Yet, no general consensus has been reached regarding which particular solution among them should be preferred according to each case. This unsatisfactory situation follows from the empirical nature of traditional approaches, especially regarding the extrapolation of the Species Accumulation Curve. Fortunately, reconsidering the problem on decidedly more theoretical basis, including the consideration of general mathematical relationships universally constraining the expression of any theoretical (or rarefied) Species Accumulation Curves, allows a more relevant modeling for the extrapolation of species accumulation. In turn, this theoretical approach provides a rational key t

La taille de la ponte décroît-elle avec une plus forte densité locale des mères et/ou une plus faible qualité de l’hôte chez les lépidoptères mineurs de feuilles ? Le cas de trois espèces communes

In herbivorous insects having a concealed larval stage, such as leaf-miners and leaf-gallers, regulating the size of the clutch may be a way for ovipositing mothers to ensure optimal resource availability for future offspring. Clutch size regulation may thus serve as an adaptive response to either (i) the average level of quality of host leaves as a food resource for offspring, or (ii) to the local density of conspecific mothers, so as to prevent scramble competition among larvae. Accordingly, clutch size regulation would imply the capacity for mothers (i) to recognize the level of leaf quality through an appropriate probing process and/or (ii) to evaluate the local density of conspecific mothers. Clutch size regulation that may possibly result from either of the two preceding factors thus needs to be addressed within the guilds of mining and galling insects. In three common leaf-mining moth species I observed that the average clutch size ‘nc’ is only weakly, non significantly related to (i) the leaf-acceptance ratio ‘α’ of mothers, which mirrors the average foliar quality of the host-individual, and (ii) the density ‘μ’ of mothers making visits to host leaves, which mirrors the local density of conspecific mothers. Therefore, clutch size is not related to the local density of conspecific mothers or the average foliar quality of host individuals for these three mining speciesChez les insectes herbivores à développement larvaire sessile (tels que les insectes mineurs ou cécidogènes de la feuille-hôte), le contrôle de la taille de ponte élémentaire permet aux mères de viser à un approvisionnement optimal pour les futures larves. La taille de ponte élémentaire peut ainsi constituer une réponse adaptative aussi bien (i) au niveau moyen de qualité des feuilles de l’hôte, destinées à la consommation des larves, que (ii) à la densité locale des mères, de sorte à éviter ou au moins limiter la compétition entre larves exploitant une même feuille-hôte. Cependant, un tel contrôle de la taille de ponte suppose évidemment que les mères pondeuses soient en capacité préalable de reconnaître le niveau moyen de qualité foliaire de l’individu hôte et/ou d’apprécier approximativement la densité des mères dans leur voisinage et d’être en outre motivées à tenir compte de ces paramètres. Cette hypothétique aptitude des mères à adapter la taille de ponte en fonction des facteurs précités mérite donc d’être testée au sein de la guilde des insectes fonceurs de mines ou inducteurs de galles foliaires. Considérant ici trois espèces communes de micro-lépidoptères formant des mines foliaires, on montre que la taille de ponte élémentaire demeure substantiellement indépendante aussi bien de la qualité moyenne des feuilles-hôtes (appréciée au moyen de l’estimation de la proportion ‘α’ de feuilles potentiellement acceptables par les mères) que de la densité des mères (appréciée indirectement au moyen de la densité ‘μ’ de visites probatoires reçues par feuille). Pour ces trois espèces au moins, les précautions maternelles apparaissent donc se limiter au choix de l’espèce-hôte puis à la sélection des feuilles considérées acceptables pour ponte, au sein de l’individu-hôte, sans que la taille de ponte soit elle-même un levier adaptati

An information theoretic necessary condition for perfect reconstruction

This article proposes a new information theoretic necessary condition for reconstructing a discrete random variable $X$ based on the knowledge of a set of discrete functions of $X$. The reconstruction condition is derived from the Shannon's Lattice of Information (LoI) \cite{Shannon53} and two entropic metrics proposed respectively by Shannon and Rajski. This theoretical material being relatively unknown and/or dispersed in different references, we provide a complete and synthetic description of the LoI concepts like the total, common and complementary informations with complete proofs. The two entropic metrics definitions and properties are also fully detailled and showed compatible with the LoI structure. A new geometric interpretation of the Lattice structure is then investigated that leads to a new necessary condition for reconstructing the discrete random variable $X$ given a set $\{ X_0$,...,$X_{n-1} \}$ of elements of the lattice generated by $X$. Finally, this condition is derived in five specific examples of reconstruction of $X$ from a set of deterministic functions of $X$: the reconstruction of a symmetric random variable from the knowledge of its sign and of its absolute value, the reconstruction of a binary word from a set of binary linear combinations, the reconstruction of an integer from its prime signature (Fundamental theorem of arithmetics) and from its reminders modulo a set of coprime integers (Chinese reminder theorem), and the reconstruction of the sorting permutation of a list from a set of 2-by-2 comparisons. In each case, the necessary condition is shown compatible with the corresponding well-known results.Comment: 17 pages, 9 figure

Formal Security Proofs via Doeblin Coefficients: Optimal Side-channel Factorization from Noisy Leakage to Random Probing

Masking is one of the most popular countermeasures to side- channel attacks, because it can offer provable security. However, depend- ing on the adversary’s model, useful security guarantees can be hard to provide. At first, masking has been shown secure against t-threshold probing adversaries by Ishai et al. at Crypto’03. It has then been shown secure in the more generic random probing model by Duc et al. at Euro- crypt’14. Prouff and Rivain have introduced the noisy leakage model to capture more realistic leakage at Eurocrypt’13. Reduction from noisy leakage to random probing has been introduced by Duc et al. at Euro- crypt’14, and security guarantees were improved for both models by Prest et al. at Crypto’19, Duc et al. in Eurocrypt’15/J. Cryptol’19, and Masure and Standaert at Crypto’23. Unfortunately, as it turns out, we found that previous proofs in either random probing or noisy leakage models are flawed, and such flaws do not appear easy to fix. In this work, we show that the Doeblin coefficient allows one to over- come these flaws. In fact, it yields optimal reductions from noisy leakage to random probing, thereby providing a correct and usable metric to properly ground security proofs. This shows the inherent inevitable cost of a reduction from the noisy leakages to the random probing model. We show that it can also be used to derive direct formal security proofs using the subsequence decomposition of Prouff and Rivain

Side-Channel Expectation-Maximization Attacks

Block ciphers are protected against side-channel attacks by masking. On one hand, when the leakage model is unknown, second-order correlation attacks are typically used. On the other hand, when the leakage model can be profiled, template attacks are prescribed. But what if the profiled model does not exactly match that of the attacked device? One solution consists in regressing on-the-fly the scaling parameters from the model. In this paper, we leverage an Expectation-Maximization (EM) algorithm to implement such an attack. The resulting unprofiled EM attack, termed U-EM, is shown to be both efficient (in terms of number of traces) and effective (computationally speaking). Based on synthetic and real traces, we introduce variants of our U-EM attack to optimize its performance, depending on trade-offs between model complexity and epistemic noise. We show that the approach is flexible, in that it can easily be adapted to refinements such as different points of interest and number of parameters in the leakage model

Age-related impairment in insulin release: the essential role of ϐ(2)-adrenergic receptor.

In this study, we investigated the significance of ϐ (2)-adrenergic receptor (ϐ (2)AR) in age-related impaired insulin secretion and glucose homeostasis. We characterized the metabolic phenotype of ϐ (2)AR-null C57Bl/6N mice (ϐ (2)AR(-/-)) by performing in vivo and ex vivo experiments. In vitro assays in cultured INS-1E ϐ-cells were carried out in order to clarify the mechanism by which ϐ (2)AR deficiency affects glucose metabolism. Adult ϐ (2)AR(-/-) mice featured glucose intolerance, and pancreatic islets isolated from these animals displayed impaired glucose-induced insulin release, accompanied by reduced expression of peroxisome proliferator-activated receptor (PPAR) γ, pancreatic duodenal homeobox-1 (PDX-1), and GLUT2. Adenovirus-mediated gene transfer of human ϐ (2)AR rescued these defects. Consistent effects were evoked in vitro both upon ϐ (2)AR knockdown and pharmacologic treatment. Interestingly, with aging, wild-type (ϐ (2)AR(+/+)) littermates developed impaired insulin secretion and glucose tolerance. Moreover, islets from 20-month-old ϐ (2)AR(+/+) mice exhibited reduced density of ϐ (2)AR compared with those from younger animals, paralleled by decreased levels of PPARγ, PDX-1, and GLUT2. Overexpression of ϐ (2)AR in aged mice rescued glucose intolerance and insulin release both in vivo and ex vivo, restoring PPARγ/PDX-1/GLUT2 levels. Our data indicate that reduced ϐ (2)AR expression contributes to the age-related decline of glucose tolerance in mice

Removing the Field Size Loss from Duc et al.\u27s Conjectured Bound for Masked Encodings

At Eurocrypt 2015, Duc et al. conjectured that the success rate of a side-channel attack targeting an intermediate computation encoded in a linear secret-sharing, a.k.a masking with $d+1$ shares, could be inferred by measuring the mutual information between the leakage and each share separately. This way, security bounds can be derived without having to mount the complete attack. So far, the best proven bounds for masked encodings were nearly tight with the conjecture, up to a constant factor overhead equal to the field size, which may still give loose security guarantees compared to actual attacks. In this paper, we improve upon the state-of-the-art bounds by removing the field size loss, in the cases of Boolean masking and arithmetic masking modulo a power of two. As an example, when masking in the AES field, our new bound outperforms the former ones by a factor $256$. Moreover, we provide theoretical hints that similar results could hold for masking in other fields as well

Biogeographic variability of coastal perennial grasslands at the European scale

Question: Coastal environments have often been described as azonal. While this characteristic is clear for the foredune system, it seems less evident for more inland fixed dunes, which host habitats of major conservation concern, whose features seem to be more related to local climatic conditions. We hypothesized that, unlike other coastal habitats, dune perennial grasslands differ floristically and structurally across their European range and that patterns of variation are linked to the corresponding climate. Location: European coasts (Atlantic Ocean, Baltic, Mediterranean, Black Sea). Methods: We used a large data set of phytosociological relevés, representative of coastal grasslands throughout their European range. The role of climatic variables (temperature, precipitation and continentality) in determining the variability in species composition and vegetation structure (by means of life forms) was investigated through CCA, DCA and GLM. The degree of concentration of species occurrences within groups was calculated through the Phi coefficient. Results: Through multivariate analyses we identified seven major types of coastal grassland, corresponding to different geographic areas. The groups significantly differed in their climatic envelope, as well as in their species composition and community structure. Conclusion: Our results confirm the hypothesis that coastal dune perennial grasslands are subjected to local climate, which exerts significant effects on both floristic composition and community structure. As a consequence, coastal grasslands are particularly prone to the effect of possible climate change, which may alter species composition and distribution, and lead to shifts in the distribution of native plant communities. © 2017 International Association for Vegetation Scienc

An annotated checklist of the jumping plant-lice (Insecta: Hemiptera: Psylloidea) from the Mercantour National Park, with seven new records for France and one new synonymy

A total of 68 psyllid species are listed from the Mercantour National Park in Southeast France, where a targeted collecting campaign was conducted between 2009 and 2012, as part of the project "ATBI+M" Mercantour. The insects were collected using Malaise traps, flight intercept traps and sweep nets to sample in the vegetation. Additional information on distribution, biology and host-plants is provided for each species. Seven species are recorded for the first time from France: Craspedolepta artemisiae (Foerster, 1848), Craspedolepta nebulosa (Zetterstedt, 1828), Cacopsylla propinqua (Schaefer, 1949), Cyamophila prohaskai (Priesner, 1927), Eryngiofaga cf. refuga (Loginova, 1966), Bactericera parastriola Conci, Ossiannilsson & Tamanini, 1988 and Trioza flixiana Burckhardt & Lauterer, 2002. Trioza (Trioza) rapisardai Conci & Tamanini, 1984 is a new subjective synonym of Trioza brachyceraea Hodkinson & White, 1979, which was previously known only from the male holotype. The abundance, distribution and introduction status of some species are discussed

Conservation assessments and Red Listing of the endemic Moroccan flora (monocotyledons)

Morocco constitutes an important centre of plant diversity and speciation in the Mediterranean Basin. However, numerous species are threatened by issues ranging from human activities to global climatic change. In this study, we present the conservation assessments and Red Listing of the endemic Moroccan monocotyledons according to International Union for Conservation of Nature (IUCN) criteria and categories. For each species, we include basic taxonomic information, local names and synonyms, uses, a distribution map, extent of occurrence, area of occupancy, population size and trend, a description of habitats and ecological requirements, and a discussion of the threats affecting the species and habitats. We assessed the threatened status of the endemic Moroccan monocotyledons at the species level (59 species) using the IUCN Red List criteria and categories (Version 3.1). This study shows the high extinction risk to the Moroccan monocotyledon flora, with 95% of threatened species (20% Critically Endangered, 50% Endangered, 25% Vulnerable) and only 5% not threatened (2% Near Threatened and 3% Least Concern). The flora is thus of conservation concern, which is poorly recognized, both nationally and internationally. The study presents the first part and so far the only national IUCN Red Data List for a large group of Moroccan plants, and thus provides an overview of the threatened Moroccan flora. This IUCN Red List is an important first step towards the recognition of the danger to Moroccan biodiversity hotspots, conservation of threatened species and the raising of public awareness at national and international levels