44 research outputs found
Diatom communities in thermo-mineral springs of Galicia (NW Spain)
[Abstract] The species composition of diatom assemblages was studied in five unpolluted thermo-mineral springs in Galicia (NW Spain). Three are considered hot and two cold, and some contain hydrogen sulphide. A total of 68 taxa (24 genera) have been recorded. The Shannon–Wiener diversity index (H′) ranged between 0.63 and 2.01. The nMDS ordination showed that diatom assemblage composition was influenced mostly by conductivity, temperature and hydrogen sulphide concentration. Diatom assemblages found in the Galician springs differed from those in springs of other geographical locations with similar physical and chemical characteristics. The most species-rich genera were Nitzschia and Achnanthidium with 10 and 8 species, respectively. Achnanthidium exiguum and Achnanthidium saprophilum had the widest distribution. Denticula thermalis and Achnanthidium caledonicum were found in environments with relatively low mineralization and low temperature, whereas Rhopalodia gibberula, Rhopalodia operculata and Fragilaria crotonensis were found in mineral-rich springs with high temperatures. Achnanthidium exiguum, A. saprophilum, Achnanthes coarctata, Achnanthes exigua var. elliptica, Mayamaea atomus, Eunotia implicata, Gomphonema minusculum, Gomphonema minutum and Cosmioneis pusilla were present in the spring with high H2S content
Evaluation of the effect of different insecticides on the survival and capacity of 2 Eretmocerus mundus Mercet to control Bemisia tabaci (Gennadius) populations
Two different experiments were carried out to evaluate three insecticides. In the 24 first one, the effect of two insecticides, methomyl and indoxacarb, on pupae and 25 adults of the whitefly Bemisia tabaci (Gennadius) parasitoid Eretmocerus mundus 26 Mercet was evaluated under laboratory and greenhouse conditions, using sweet 27 pepper (Capsicum annuum L.) plants. In the second experiment, oxamyl was 28 tested to study its effect on the ability of E. mundus to parasitize and control B. 29 tabaci in sweet pepper plants, using a greenhouse cage evaluation. Methomyl and 30 indoxacarb caused low mortality of E. mundus pupae (17.6 and 7.8% 31 respectively), although methomyl mortality was significantly higher. Methomyl 32 produced 100% mortality on E. mundus adults with fresh and 24 hour-old 33 residues on leaves, significantly higher than the mortality produced by indoxacarb 34 (values ranged from 43.9 to 34.4%). The harmful effect of methomyl persisted for 35 a long time (up to 60 days). The results of the experiment with oxamyl showed 36 that E. mundus controlled whitefly population, without significant interaction 37 between the presence of the parasitoid and insecticide on whitefly mortality. 38 Whitefly mortality in the presence of the parasitoid was 87.8%, significantly higher 39 than the mortality in the absence of E. mundus (59.3%). Oxamyl did not produce 40 a significant effect on the emergence of E. mundus adults. Application of the 41 products in IPM programs is discussed
Biomass and clonal architecture of the cordgrass Spartina patens (Poaceae) as an invasive species in two contrasted coastal habitats on the Atlantic coast of the Iberian Peninsula
Background and aims – The spread of invasive exotic species is one of the most important threats for salt marshes and cordgrasses (genus Spartina) are among the most invasive halophytes. Recent analyses have revealed low levels of genetic diversity within the European cordgrass Spartina patens, clarifying that it was introduced from a narrow genetic pool of plants from North America. As biomass and intratussock structure are key functional traits in the ecological behaviour of cordgrasses, our aim was to document this here for the first time in Spartina patens in Europe. Methods – This work analyses above- and below-ground biomass and intratussock structure for two Spartina patens populations in Southern Spain in the two main invaded habitats in Europe, coastal dunes and brackish marshes. Key results – Spartina patens showed higher above-ground biomass and higher above: below-ground biomass ratio in the brackish marsh than on the coastal dunes due to higher live shoot densities with similar shoot heights. Sexual reproduction of Spartina patens was very limited in both studied populations since only a few inflorescences were recorded in just one tussock in the marsh. Conclusions – Our results for introduced Spartina patens in Spain are compared with those recorded for cohabiting cordgrasses, the native European Spartina maritima and the invasive Spartina densiflora, as well as with Spartina patens in North American marshes. Spartina patens appears as a species with moderate invasive potential in European coastal marshes and dunes since it shows very low sexual reproduction but a high phenotypic plasticity, which would support its invasive capacity. Eradication efforts are most cost effective in the early stage of infestation, when population sizes are still relatively small, and should thus be a focus of the control efforts of S. patens in the Southwest Iberian Peninsula as well as in other European areas, where this cordgrass is still not very abundant
Performance assessment of 40 Gbit/s off-the-shelf network cards for virtual network probes in 5G networks
Incoming 5G networks will evolve regarding how they operate due to the use of virtualization technologies. Network functions that are necessary for communication will be virtual and will run on top of commodity servers. Among these functions, it will be essential to deploy monitoring probes, which will provide information regarding how the network is behaving, which will be later analyzed for self-management purposes. However, to date, the network probes have needed to be physical to perform at link-rates in high-speed networks, and it is challenging to deploy them in virtual environments. Thus, it will be necessary to rely on bare-metal accelerators to deal with existing input/output (I/O) performance problems. Next, to control the costs of implementing these virtual network probes, our approach is to leverage the capabilities that current commercial off-the-shelf network cards provide for virtual environments. Specifically, to this end, we have implemented HPCAP40vf, which is a driver that is GPL-licensed and available for download, for network capture in virtual machines. This driver handles the communication with an Intel XL710 40 Gbit/s commercial network card to enable a network monitoring application run within a virtual machine. To store the captured traffic, we have relied on NVMe drives due to their high transference rate, as they are directly connected to the PCIe bus. We have assessed the performance of this approach and compared it with DPDK, in terms of both capturing and storing the network traffic by measuring the achieved data rates. The evaluation has taken into account two virtualization technologies, namely, KVM and Docker, and two access methods to the underlying hardware, namely, VirtIO and PCI passthrough. With this methodology, we have identified bottlenecks and determined the optimal solution in each case to reduce overheads due to virtualization. This approach can also be applied to the development of other performance-hungry virtual network functions. The obtained results demonstrate the feasibility of our proposed approach: when we correctly use the capabilities that current commercial network cards provide, our virtual network probe can monitor at 40 Gbit/s with full packet capture and storage and simultaneously track the traffic among other virtual network functions inside the host and with the external networkThis work has been partially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under the project TRÁFICA (MINECO/FEDER TEC2015-69417-C2-1-R),and by the European Commission under the project H2020METRO-HAUL (Project ID:761727
Comparison of Cardiovascular Risk Factors for Coronary Heart Disease and Stroke Type in Women
Background Cardiovascular risk factors have differential effects on various manifestations of cardiovascular disease, but to date direct formal comparisons are scarce, have been conducted primarily in men, and include only traditional risk factors. Methods and Results Using data from the multi-ethnic Women's Health Initiative Observational Study, we used a case-cohort design to compare 1731 women with incident cardiovascular disease during follow-up to a cohort of 1914 women. The direction of effect of all 24 risk factors (including various apolipoproteins, hemoglobin A1c, high-sensitivity C-reactive protein, N-terminal pro-brain natriuretic peptide, and tissue plasminogen activator antigen) was concordant for coronary heart disease (CHD, defined as myocardial infarction and CHD death) and ischemic stroke; however, associations were generally stronger with CHD. Significant differences for multiple risk factors, including blood pressure, lipid levels, and measures of inflammation, were observed when comparing the effects on hemorrhagic stroke with those on ischemic outcomes. For instance, multivariable adjusted hazard ratios per standard deviation increase in non-high-density lipoprotein cholesterol were 1.16 (95% confidence interval, 1.06-1.28) for CHD, 0.97 (0.88-1.07) for ischemic stroke, and 0.76 (0.63-0.91) for hemorrhagic stroke ( P<0.05 for equal association). Model discrimination was better for models predicting CHD or ischemic stroke than for models predicting hemorrhagic stroke or a combined end point. Conclusions Cardiovascular risk factors have largely similar effects on incidence of CHD and ischemic stroke in women, although the magnitude of association varies. Determinants of ischemic and hemorrhagic stroke substantially differ, underscoring their distinct biology. Cardiovascular disease risk may be more accurately reflected when combined cardiovascular disease or cerebrovascular outcomes are broken down into different first manifestations, or when restricted to ischemic outcomes
Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe
Biomass and clonal architecture of the cordgrass Spartina patens (Poaceae) as an invasive species in two contrasted coastal habitats on the Atlantic coast of the Iberian Peninsula
Background and aims – The spread of invasive exotic species is one of the most important threats for salt marshes and cordgrasses (genus Spartina ) are among the most invasive halophytes. Recent analyses have revealed low levels of genetic diversity within the European cordgrass Spartina patens, clarifying that it was introduced from a narrow genetic pool of plants from North America. As biomass and intratussock structure are key functional traits in the ecological behaviour of cordgrasses, our aim was to document this here for the first time in Spartina patens in Europe.Methods – This work analyses above- and below-ground biomass and intratussock structure for two Spartina patens populations in Southern Spain in the two main invaded habitats in Europe, coastal dunes and brackish marshes.Key results – Spartina patens showed higher above-ground biomass and higher above: below-ground biomass ratio in the brackish marsh than on the coastal dunes due to higher live shoot densities with similar shoot heights. Sexual reproduction of Spartina patens was very limited in both studied populations since only a few inflorescences were recorded in just one tussock in the marsh.Conclusions – Our results for introduced Spartina patens in Spain are compared with those recorded for cohabiting cordgrasses, the native European Spartina maritima and the invasive Spartina densiflora, as well as with Spartina patens in North American marshes. Spartina patens appears as a species with moderate invasive potential in European coastal marshes and dunes since it shows very low sexual reproduction but a high phenotypic plasticity, which would support its invasive capacity. Eradication efforts are most cost effective in the early stage of infestation, when population sizes are still relatively small, and should thus be a focus of the control efforts of S. patens in the Southwest Iberian Peninsula as well as in other European areas, where this cordgrass is still not very abundant
Biomass and clonal architecture of the cordgrass Spartina patens (Poaceae) as an invasive species in two contrasted coastal habitats on the Atlantic coast of the Iberian Peninsula
Background and aims – The spread of invasive exotic species is one of the most important threats for salt marshes and cordgrasses (genus Spartina ) are among the most invasive halophytes. Recent analyses have revealed low levels of genetic diversity within the European cordgrass Spartina patens, clarifying that it was introduced from a narrow genetic pool of plants from North America. As biomass and intratussock structure are key functional traits in the ecological behaviour of cordgrasses, our aim was to document this here for the first time in Spartina patens in Europe.Methods – This work analyses above- and below-ground biomass and intratussock structure for two Spartina patens populations in Southern Spain in the two main invaded habitats in Europe, coastal dunes and brackish marshes.Key results – Spartina patens showed higher above-ground biomass and higher above: below-ground biomass ratio in the brackish marsh than on the coastal dunes due to higher live shoot densities with similar shoot heights. Sexual reproduction of Spartina patens was very limited in both studied populations since only a few inflorescences were recorded in just one tussock in the marsh.Conclusions – Our results for introduced Spartina patens in Spain are compared with those recorded for cohabiting cordgrasses, the native European Spartina maritima and the invasive Spartina densiflora, as well as with Spartina patens in North American marshes. Spartina patens appears as a species with moderate invasive potential in European coastal marshes and dunes since it shows very low sexual reproduction but a high phenotypic plasticity, which would support its invasive capacity. Eradication efforts are most cost effective in the early stage of infestation, when population sizes are still relatively small, and should thus be a focus of the control efforts of S. patens in the Southwest Iberian Peninsula as well as in other European areas, where this cordgrass is still not very abundant