A Posteriori Stabilized Sixth-Order Finite Volume Scheme with Adaptive Stencil Construction:Basics for the 1D Steady-State Hyperbolic Equations

We propose an adaptive stencil construction for high-order accurate finite volume schemes a posteriori stabilized devoted to solve one-dimensional steady-state hyperbolic equations.High accuracy(up to the sixth-order presently)is achieved,thanks to polynomial recon-structions while stability is provided with an a posteriori MOOD method which controls the cell polynomial degree for eliminating non-physical oscillations in the vicinity of dis-continuities.We supplemented this scheme with a stencil construction allowing to reduce even further the numerical dissipation.The stencil is shifted away from troubles(shocks,discontinuities,etc.)leading to less oscillating polynomial reconstructions.Experimented on linear,Burgers',and Euler equations,we demonstrate that the adaptive stencil technique manages to retrieve smooth solutions with optimal order of accuracy but also irregular ones without spurious oscillations.Moreover,we numerically show that the approach allows to reduce the dissipation still maintaining the essentially non-oscillatory behavior.

Transcriptomes of Litopenaeus vannamei reveal modulation of antioxidant system induced by dietary archaeal carotenoids

Oxidative stress induced by factors such as ammonia nitrogen has become a major issue in shrimp farming.The effects of carotenoids on the growth and antioxidant capability of Litopenaeus vannamei juveniles were investigated in this study using dietary archaeal carotenoids supplementation.For four weeks,shrimp were given diets containing 0 mg/kg(Ctrl)and 55.98 mg/kg(Car)archaeal carotenoids.Dietary archaeal carotenoids significantly enhanced the astaxanthin content in shrimp muscles and carapaces,as well as the superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activity(P<0.05).The malonaldehyde(MDA)content in Car group significantly decreased(P<0.05).The transcriptome analysis was conducted to determine the molecular processes in response to archaeal carotenoids supplementation.A total of 1536 differentially expressed genes(DEGs)were detected,including 538 upregulated DEGs and 998 downregulated DEGs.GO functional enrichment analysis between Ctrl and Car indicated that 26 GO terms including extracellular region,metabolic process,and proteolysis were enriched.The KEGG pathway enrichment analysis revealed that the amino sugar and nucleotide sugar metabolism,cysteine and methionine metabolism,glycine serine and threonine metabolism,and amino acid biosynthesis were enriched.Archaeal carotenoids influenced the expression of several important genes involved in reactive oxygen species(ROS)generation,Nrf2 signaling,and antioxidant enzymes.Seven DEGs were chosen to confirm the RNA-Seq data using qRT-PCR.The genes and pathways discovered in this work assist to elucidate the molecular processes through which archaeal carotenoid enhances L.vannamei antioxidative system.

Evaluation of total protein,peroxidase,and nutrients measured by pXRF for the determination of tissue rejuvenation/reinvigoration of Eucalyptus microcorys

Ontogenetic aging of tissues and the gradual decrease of adventitious rooting are known challenges for the clonal propagation of woody species,hampering clonal forestry programs.This study examined possible signatures of tissue rejuvenation/reinvigoration in different propagated materials of Eucalyptus microcorys by analyzing the total protein profile,peroxidase activity,macro-and micronutrient contents,and adventitious rooting of mini cuttings.The analyses were performed on E.microcorys shoots which were successfully obtained by seminal and grafting propagation,micropropagation with epicormic shoots,and indirect organogenesis.Among four mature trees used in the propagation,tissues from the one with the best propagation results were investigated for signs of tissue rejuvenation and/or reinvigoration.Five individuals from each technique were randomly selected and transferred to a semi-hydroponic"channel"system.After four weeks in the seedbed,the total protein,peroxidase activity,nutrient content and rooting of the mini cuttings were evaluated.SDS-PAGE enabled the differentiation of leaf samples obtained by grafting from the other propagation techniques,as revealed by two distinct bands.Materials obtained by micropropagation with epicormic shoots showed the highest peroxidase activity,while those obtained by seminal propagation and from the selected mature tree showed the lowest peroxidase activity.A portable X-ray fluorescence spectroscope(pXRF)identified adequate nutrient content in most of the nutrients tested in materials obtained by seminal and grafting propagation,and by indirect organogenesis.The analysis of adventitious rooting showed that the highest rooting percentage was observed in mini cuttings from seminal propagation(75%)followed by indirect organogenesis(35%).Based on principal component analysis,it was concluded that rooting of mini cuttings from both seminal propagation and indirect organogenesis was associated with phosphorous,sulphur,and potassium contents,which suggests a higher level of tissue rejuvenation/reinvigoration in these propagated plants.Further studies are recommended to search for other methods that present similarities with the responses to adventitious rooting in forest species and thus optimize the rescue and propagation of plants with distinct ontogenetic stages.

Decline of semen quality among 10 932 males consulting for couple infertility over a 20-year period in Marseille, France

Semen from 10 932 male partners of infertile couples was analysed and sperm parameter trends were evaluated at the Reproduction Biology Laboratory of the University Hospital of Marseille （France） between 1988 and 2007. After 3-6 days of abstinence, semen samples were collected. Measurements of seminal fluid volume, pH, sperm concentration, total sperm count, motility and detailed morphology of spermatozoa were performed. Sperm parameters were analysed on the entire population and in men with normal total numeration （ 〉~ 40 million per ejaculate）. The whole population demonstrated declining trends in sperm concentration （1.5% per year）, total sperm count （1.6% per year）, total motility （0.4% per year）, rapid motility （5.5% per year） and normal morphology （2.2% per year）. In the group of selected samples with total normal sperm count, the same trends of sperm quality deterioration with time were observed. Our results clearly indicate that the auality of semen decreased in this population over the study period.

Vegetation Composition and Structure of Some NeotropicaMountain Grasslands in Brazil

The description and understanding of plant communities is fundamental for the implementation of conservation or restoration programs, especially when these communities are highly threatened and need to be restored.Campos rupestres, some Neotropical mountain grasslands located in central Brazil and part of the Cerrado biome(covering 2 million km2) host unique plant communities, currently threatened by quarrying and mining.The grassy matrix of campos rupestres, has long been considered a rich mosaic under the control of local topography and the nature of substrate, but this affirmation has not been well studied.We analyzed whether plant communities varied in relation to edaphic factors within the stony substrate and the sandy substrate of this grassy matrix.We selected 5 sites where occur both grasslands on stony substrate and on sandy substrate, and we carried out vegetation surveys and soil analyses.We counted 222 plant species within our communities, among which38.6% are exclusively found on campos rupestres.Our results show that both soil-types are strongly acidic, nutrient poor and exhibit a seasonal variation.Phosphorus increases and p H and organic carbon decrease during the dry season.Stony soils areslightly richer in nutrients than sandy soils and differences in soil granulometry and composition have led to the formation of distinct plant communities.Some species are confined to either one or the other grassland-type, which makes the plant composition of each community unique.Variations in edaphic factors generate heterogeneous grasslands favorable to a high plant diversity.Conservation programs and restoration actions have to maintain or recreate this heterogeneity.The presence of distinct plant communities implies that different strategies might be adopted to improve the restoration of these ecosystems.

Efficacy of a Biorevitalizing-Filler Solution on All Skin Aspects: 10 Years Approach through <i>in Vitro</i>Studies and Clinical Trials

Introduction: Skin aging is the result of many cellular dysfunctions over time particularly the fibroblasts and the keratinocytes. These dysfunctions could be decelerated by the preventive effects of some skin treatments such as Intradermal injections. NCTF 135HA has a polycomponent formulation designed to improve the efficacy of non-cross linked hyaluronic acid (as a micro-filler) on fibroblasts function. Although NCTF 135HA has been used by aesthetic practitioners since 20 years, we have analyzed all in vitro, ex vivo and in vivo studies during past 10 years in order to summarized its anti-aging effect. Methods: In these series of studies, the known effects of HA have been evaluated with this boosted formula. Collagen I synthesis, antiglycation effect and contractile forces developed by fibroblasts were studied. Fibroblasts and keratinocytes proliferations were evaluated in monolayer cells culture. The filling effect thanks to NCTF 135HA injection was ex vivo performed by fringe projection and the protective effect of NCTF 135HA against solar irradiation was performed ex vivo to study proliferation rate, elastin and collagen expression. Two clinical trials were performed on women to evaluate the anti-aging effect of NCTF 135HA injection. Hydration, firmness, radiance, wrinkles size, pore size, thickness and density of the dermis were analyzed. Results: Collagen I, anti-AGE products, cell proliferation and contractile forces were significantly increased with NCTF 135HA in culture medium. Ex vivo studies showed that NCTF 135HA increased, cells proliferation rate, elastin and collagen production. In addition, the filling effect of the NCTF 135HA is significantly superior to placebo. The first clinical trial shows that NCTF 135HA injection significantly increased tonicity, hydration and radiance of the skin and significantly decreased wrinkle score. The second clinical trial demonstrated that NCTF 135HA injection significantly increased dermis density and thickness, skin homogeneity and skin radiance and significantly decreased pore size and wrinkle depth and volume. Conclusion: In vitro, ex vivo and in vivo studies showed that this minimally invasive technique could be used in order to improve the skin quality which could have a visual effect on preventing the aging signs.

基于非结构自适应网格和嵌入边界法的残差格式研究（英文）

嵌入边界法由于在求解NS方程时能够简化网格生成问题而在计算流体领域受到越来越广泛的关注。简言之,嵌入边界法能够简化大变形和运动条件下多物理流动模拟、流固相互作用耦合问题,然而壁面边界条件的精确处理仍旧是该方法需要解决的问题。在本文工作中,为考虑壁面边界条件而在NS方程中增加了补偿项,同时采用非结构网格自适应技术保持了壁面边界条件的精度。

Comparative Study of the Effects of Thermal and Photochemical Accelerated Oxidations on Quality of “Green Type” and “Black Type” French Olive Oils

Oxidative stability of two commercial olive oils of different specificity (green type and black type) has been studied during thermal and photochemical accelerated processes through the evolution of quality indices. It might help to assure a good utilisation of olive oil. In most of works described in literature, they are measured individually. In this study, a Principal Component Analysis (PCA) has been performed to emphasize their variation and describe in concise way the quality and the safety of extra-virgin olive oil after two oxidative stresses. No difference had been detected between both type oils when they are heated. Peroxides, aldehydes and conjugated dienes and trienes were formed but rapidly degraded into final oxidation compounds, mainly acid compounds. During the photochemical process, similar changes occurred slower and the green type oil had shown better stability because of its higher phenolic content. The fatty acids had been more impacted (higher disappearance of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA)) when the oils were heated than when irradiated. Saturated fatty acids (SFA), MUFA and PUFA were the most relevant indicators to characterize non-oxidized oils and PV characterized the early stage of oil oxidation.

Morphology and Genetic Studies of Cymodocea Seagrass Genus in Tunisian Coasts

Specimens of Cymodocea(Viridiplantae,Magnoliophyta)collected on the Tunisian coasts showed a particular morphological and anatomical difference with the classical descriptions of Cymodocea nodosa(Ucria)Asch.the only species of this genus reported in the Mediterranean Sea.In order to precise the taxonomic identity of the new specimens we aimed in this work(i)to verify the identity of the new forms,(ii)to evaluate the genetic diversity of the population,(iii)to test the validity of the existing identification keys of the Tunisian Cymodocea populations.Four stations located in two regions of the Tunisian coasts were sampled.Leaf morphological and anatomical characters used in taxonomic identification were measured(e.g.,number of cross veins,shape of the apex).The genetic study was performed using three most common chloroplast markers for plant characterization(DNA barcodes rbcL,matK and trnHpsbA).The morphological study revealed the presence of three C.nodosa morphotypes,described here for the first time,while the molecular characterization did not allow the discrimination of these morphological types.In regard to these results,it would be wise to review the classical identification keys of the Cymodocea genus.

Structure, Tree Growth and Dynamics of <I>Cedrus atlantica</I>Manetti Forests in Theniet El Had National Park (N-W Algeria)

In North Africa, Cedrus atlantica forests are in decline, following decades of anthropogenic pressure and repeated drought events. Mixed C. atlantica-Quercus ilex stands located in the Theniet El Had National Park (northwestern Algeria) were considered in the present study. Based on a stratified sampling, six temporary plots were established to describe structure (species composition, density, total height, diameter and basal area) and radial growth in relation to type of stand (pure and mixed), using a dendroecological approach. The diameter distribution of C. atlantica indicated the presence of few young individuals and a poor regeneration status in all the stands. The density and basal area of C. atlantica were significantly higher in pure stands, which necessitate silvicultural operations. In contrast, Q. ilex showed a progressive dynamic, at moderate altitude. Radial growth showed a significant decline from 1980 to the 2000s. The absence of an appropriate management plan and the increase in anthropogenic effects, without ruling out a role for the current climate conditions marked by drought, seem to be the causes of C. atlantica decline.

Wild grapevine(Vitis vinifera subsp.sylvestris)in the Hyrcanian relict forests of northern Iran:an overview of current taxonomy,ecology and palaeorecords

Due to severe anthropogenic impacts on lowland and submontane zones of the Hyrcanian forests of northern Iran, wild grapevine(Vitis vinifera subsp. sylvestris), a sporadically distributed woody liana, is currently considered an endangered species. Using data from the literature and 34 studied populations, herbarium assessments and nine palynological sites, we provide an overview of its taxonomy,distribution and ecology in the first part of the investigation.The separation of the two subspecies, namely V. sylvestris subsp. anebophylla and V. sylvestris subsp. trichophylla(sensu Flora Iranica), based on their leaf indumentums, could not be confirmed by our examination of herbarium materials and field observations. Indumentum of the leaves is a result of leaf polymorphism in different Vitis specimens and can be strongly influenced by environmental conditions. Vitis vinifera subsp. sylvestris grows in a wide range of habitats including wetlands, seasonal stream sides in closed forests,alluvial beds of large rivers, sand dune shrublands and forested wetlands(alder forests). Parrotia persica and Carpinus betulus were the most frequent host species in the studied populations. In the Hyrcanian region, no pollen record of Vitis older than the Mid-or Late-Holocene has yet been established. Despite the intrinsic problem in pollen identification by normal(i.e., light) microscopy of wild from cultivated grapevines, the significant values and persistent occurrence of Vitis pollen since the Mid-Holocene(before the Bronze Age) in the Hyrcanian pollen records may imply the onset of viticulture in low-to mid-elevation sites in the region. This represents an argument to consider the Hyrcanian region as a possible domestication center for V. vinifera.However, the question of wild versus cultivated origin of grapevines in the Hyrcanian pollen records and the possible date of its domestication and/or cultivation will remain open until further palynological studies are undertaken.

Habitat Characterization of Black Flies(Diptera:Simuliidae)in the Tafna Catchment of Western Algeria

Physical Habitat characterization of black flies was performed in the Tafna Basin of Algeria, based primarily on stream size, substrate, and aquatic and riparian vegetation. A total of 143 samples were taken between April and October 2009 at 11 sampling sites in the Tafna catchment. Dams exerted an effect through a slowdown of flow and sedimentation of fine particles, eliminating coarse microhabitats favorable for black flies. Stream and substrate characteristics are key parameters that determined the microhabitats of the species. Of 10 species considered, four were widely present with significant plasticity for the stream and substrate. Four other species were more closely associated with faster streams and eroded substrate. A greater rheophilic tendency was found for Simulium bezzii (Corti), Simulium sergenti Edwards, Simulium quadrifila Grenier, Faure and Laurent and Simulium galloprovinciale Giudicelli, which represents a new record for Algeria.

What is a tree in the Mediterranean Basin hotspot?A critical analysis

Background: Tree species represent 20% of the vascular plant species worldwide and they play a crucial role in the global functioning of the biosphere. The Mediterranean Basin is one of the 36 world biodiversity hotspots, and it is estimated that forests covered 82% of the landscape before the first human impacts, thousands of years ago. However, the spatial distribution of the Mediterranean biodiversity is still imperfectly known, and a focus on tree species constitutes a key issue for understanding forest functioning and develop conservation strategies. Methods: We provide the first comprehensive checklist of all native tree taxa (species and subspecies) present in the Mediterranean-European region (from Portugal to Cyprus). We identified some cases of woody species difficult to categorize as trees that we further called "cryptic trees". We collected the occurrences of tree taxa by"administrative regions", i.e. country or large island, and by biogeographical provinces. We studied the species-area relationship, and evaluated the conservation issues for threatened taxa following IUCN criteria. Results: We identified 245 tree taxa that included 210 species and 35 subspecies, belonging to 33 families and 64 genera. It included 46 endemic tree taxa (30 species and 16 subspecies), mainly distributed within a single biogeographical unit. The countries with the highest tree richness are Greece (146 taxa), Italy (133), Albania (122), Spain (155), Macedonia (116), and Croatia (110). The species-area relationship clearly discriminated the richest central-eastern (Balkans) and northern (Alpine and Cevenno-Pyrenean) biogeographical provinces, against the five western provinces in the Iberian Peninsula. We identified 44 unrecognized "cryptic trees", representing 21% of the total trees. Among the 245 taxa identified, 19 are considered to be threatened (15 CR+EN+VU) or near threatened (4 NT) by IUCN. Conclusions: The Mediterranean-European region includes an unsuspectedly high number of tree taxa, almost 200 tree taxa more than in the central European region. This tree diversity is not distributed evenly and culminates in the central-eastern part of the Mediterranean region, whereas some large Tyrrhenian islands shelter several narrow endemic tree taxa. Few taxa are recognized as threatened in the IUCN Red list, and the vulnerability of these species is probably underestimated.

An Unconventional Divergence Preserving Finite-Volume Discretization of Lagrangian Ideal MHD

We construct an unconventional divergence preserving discretization of updated Lagrangian ideal magnetohydrodynamics(MHD)over simplicial grids.The cell-centered finite-volume(FV)method employed to discretize the conservation laws of volume,momentum,and total energy is rigorously the same as the one developed to simulate hyperelasticity equations.By construction this moving mesh method ensures the compatibility between the mesh displacement and the approximation of the volume flux by means of the nodal velocity and the attached unit corner normal vector which is nothing but the partial derivative of the cell volume with respect to the node coordinate under consideration.This is precisely the definition of the compatibility with the Geometrical Conservation Law which is the cornerstone of any proper multi-dimensional moving mesh FV discretization.The momentum and the total energy fluxes are approximated utilizing the partition of cell faces into sub-faces and the concept of sub-face force which is the traction force attached to each sub-face impinging at a node.We observe that the time evolution of the magnetic field might be simply expressed in terms of the deformation gradient which characterizes the Lagrange-to-Euler mapping.In this framework,the divergence of the magnetic field is conserved with respect to time thanks to the Piola formula.Therefore,we solve the fully compatible updated Lagrangian discretization of the deformation gradient tensor for updating in a simple manner the cell-centered value of the magnetic field.Finally,the sub-face traction force is expressed in terms of the nodal velocity to ensure a semi-discrete entropy inequality within each cell.The conservation of momentum and total energy is recovered prescribing the balance of all the sub-face forces attached to the sub-faces impinging at a given node.This balance corresponds to a vectorial system satisfied by the nodal velocity.It always admits a unique solution which provides the nodal velocity.The robustness and the accuracy of this unconventional FV scheme have been demonstrated by employing various representative test cases.Finally,it is worth emphasizing that once you have an updated Lagrangian code for solving hyperelasticity you also get an almost free updated Lagrangian code for solving ideal MHD ensuring exactly the compatibility with the involution constraint for the magnetic field at the discrete level.

Preface

This focused issue of the Communications on Applied Mathematics and Computation is in Honour of Prof.Rémi Abgrall on the Occasion of His 61th Birthday.Rémi Abgrall has been a student in mathematics(1981–1985)of Ecole Normale Supérieure de Saint Cloud(now part of ENS Lyon).After his studies in pure mathematics,he changed orientation tofluid mechanics.He did his PhD at the Laboratoire de Météorologie Dynamique(LMD)at Ecole Normale Supérieure under the supervision of Claude Basdevant.He graduated in December 1987 with a thesis on a semi-Lagrangian model of 2D turbulence,refereed by Olivier Pironneau and Marcel Lesieur.

Sterile signals generate weaker and delayed macrophage NLRP3 inflammasome responses relative to microbial signals

Inflammation is the host response to microbial infection or sterile injury that aims to eliminate the insult, repair the tissue and restore homeostasis. Macrophages and the NLRP3 inflammasome are key sentinels for both types of insult. Although it is well established that the NLRP3 inflammasome is activated by microbial products and molecules released during sterile injury, it is unclear whether the responses elicited by these different types of signals are distinct. In this study, we used lipopolysaccharide and tumor necrosis factor as prototypical microbial and sterile signal 1 stimuli, respectively, to prime the NLRP3 inflammasome. We then used the bacterial toxin nigericin and a common product released from necrotic cells, ATP, as prototypical microbial and sterile signal 2 stimuli, respectively, to trigger the assembly of the NLRP3 inflammasome complex in mouse and human macrophages. We found that NLRP3 inflammasome responses were weakest when both signal 1 and signal 2 were sterile, but responses were faster and stronger when at least one of the two signals was microbial. Ultimately, the most rapid and potent responses were elicited when both signals were microbial. Together, these data suggest that microbial versus sterile signals are distinct, both kinetically and in magnitude, in their ability to generate inflammasome-dependent responses. This hierarchy of NLRP3 responses to sterile versus microbial stimuli likely reflects the urgent need for the immune system to respond rapidly to the presence of infection to halt pathogen dissemination.

A COVID-19 epidemic model with latency period

At the beginning of a COVID-19 infection,there is a period of time known as the exposed or latency period,before an infected person is capable of transmitting the infection to another person.We develop two differential equations models to account for this period.The first is a model that incorporates infected persons in the exposed class,before transmission is possible.The second is a model that incorporates a time delay in infected persons,before transmission is possible.We apply both models to the COVID-19 epidemic in China.We estimate the epidemiological parameters in the models,such as the transmission rate and the basic reproductive number,using data of reported cases.We thus evaluate the role of the exposed or latency period in the dynamics of a COVID-19 epidemic.

Clarifying predictions for COVID-19 from testing data: The example of New York State

With the spread of COVID-19 across the world,a large amount of data on reported cases has become available.We are studying here a potential bias induced by the daily number of tests which may be insufficient or vary over time.Indeed,tests are hard to produce at the early stage of the epidemic and can therefore be a limiting factor in the detection of cases.Such a limitation may have a strong impact on the reported cases data.Indeed,some cases may be missing from the official count because the number of tests was not sufficient on a given day.In this work,we propose a new differential equation epidemic model which uses the daily number of tests as an input.We obtain a good agreement between the model simulations and the reported cases data coming from the state of New York.We also explore the relationship between the dynamic of the number of tests and the dynamics of the cases.We obtain a good match between the data and the outcome of the model.Finally,by multiplying the number of tests by 2,5,10,and 100 we explore the consequences for the number of reported cases.

A combined computational pipeline to detect circular RNAs in human cancer cells under hypoxic stress

Hypoxia is associated with several diseases,including cancer.Cells that are deprived of adequate oxygen supply trigger tran-scriptional and post-transcriptional responses,which control cellular pathways such as angiogenesis,proliferation,and metabolic adaptation.Circular RNAs(circRNAs)are a novel class of mainly non-coding RNAs,which have been implicated in multiple cancers and attract increasing attention as potential biomarkers.Here,we characterize the circRNA signatures of three different cancer cell lines from cervical(HeLa),breast(MCF-7),and lung(A549)cancer under hypoxia.In order to reliably detect circRNAs,we integrate available tools with custom approaches for quantification and statistical analysis?Using this consolidated computational pipeline,we identify?12000 circRNAs in the three cancer celUines.Their molecular characteristics point to an involvement of complementary RNA sequences as well as trans-acting factors in circRNA biogenesis,such as the RNA-binding protein HNRNPC-Notably,we detect a number of circRNAs that are more abundant than their linear counterparts.In addition,64 circRNAs significantly change in abundance upon hypoxia,in most cases in a cell type-specific manner.In summary,we present a comparative circRNA profiling in human cancer cell lines,which promises novel insights into the biogenesis and function of circRNAs under hypoxic stress.

Invasive rats strengthen predation pressure on bird eggs in a South Pacific island rainforest

Invasive rats （Rattus spp.） are known to have pervasive impacts on island birds, particularly on their nesting success. To conserve or restore bird populations, numerous invasive rat control or eradication projects are undertaken on islands worldwide. However, such projects represent a huge investment and the decision-making process requires proper assessment of rat impacts. Here, we assessed the influence of two sympatric invasive rats （Rattus rattus and R. exulans） on native bird eggs in a New Caledonian rainforest, using artificial bird-nest monitoring. A total of 178 artificial nests containing two eggs of three different sizes were placed either on the ground or 1.5 m high and monitored at the start of the birds＇ breeding season. Overall, 12.4% of the nests were depredated during the first 7 days. At site 1, where nests were monitored during 16 days, 41.8% of the nests were depredated. The main predator was the native crow Corvus moneduloides, responsible for 62.9% of the overall predation events. Rats were responsible for only 22.9% of the events, and ate only small and medium eggs at both heights. Our experiment suggests that in New Caledonia, predation pressure by rats strengthens overall bird-nest predation, adding to that by native predators, Experimental rat control operations may allow reduced predation pressure on nests as well as the recording of biodiversity responses after rat population reduction.