5,180 research outputs found
Factors limiting the establishment of canopy-forming algae on artificial structures
Macroalgal canopies are important ecosystem engineers, contributing to coastal productivity and supporting a rich assemblage of associated flora and fauna. However, they are often absent from infrastructures such as coastal defences and there has been a worldwide decline in their distribution in urbanised coastal areas. The macroalga Fucus spiralis is the only high-shore canopy forming species present in the Azores. It is widely distributed in the archipelago but is never found on coastal infrastructures. Here we evaluate factors that may potentially limit its establishment on artificial structures. A number of observational and manipulative experiments were used to test the hypotheses that: (i) limited-dispersal ability limits the colonisation of new plants onto artificial structures, (ii) vertical substratum slope negatively influences the survivorship of recruits, and (iii) vertical substratum slope also negatively influences the survivorship and fitness of adults. Results showed that the limited dispersal from adult plants may be a more important factor than slope in limiting the species ability to colonise coastal infrastructures, since the vertical substratum slope does not affect its fitness or survivorship.European Regional Development Fund (ERDF); COMPETE - Operational Competitiveness Programme; FCT - Foundation for Science and Technology; cE3c funding. GMM was supported by a postdoctoral grant awarded by FCT (SFRH/BDP/63040/2009). ACLP was funded by a FRCT research grant M3.1.5/F/098/2012. Support was also provided by CIRN/UAc (Centre of Natural Resources of University of the Azores).info:eu-repo/semantics/publishedVersio
Women's Experiences and Views about Costs of Seeking Malaria Chemoprevention and other Antenatal Services: A Qualitative Study from two Districts in Rural Tanzania.
The Tanzanian government recommends women who attend antenatal care (ANC) clinics to accept receiving intermittent preventive treatment against malaria during pregnancy (IPTp) and vouchers for insecticide-treated nets (ITNs) at subsidized prices. Little emphasis has been paid to investigate the ability of pregnant women to access and effectively utilize these services. To describe the experience and perceptions of pregnant women about costs and cost barriers for accessing ANC services with emphasis on IPTp in rural Tanzania. Qualitative data were collected in the districts of Mufindi in Iringa Region and Mkuranga in Coast Region through 1) focus group discussions (FGDs) with pregnant women and mothers to infants and 2) exit-interviews with pregnant women identified at ANC clinics. Data were analyzed manually using qualitative content analysis methodology. FGD participants and interview respondents identified the following key limiting factors for women's use of ANC services: 1) costs in terms of money and time associated with accessing ANC clinics, 2) the presence of more or less official user-fees for some services within the ANC package, and 3) service providers' application of fines, penalties and blame when failing to adhere to service schedules. Interestingly, the time associated with travelling long distances to ANC clinics and ITN retailers and with waiting for services at clinic-level was a major factor of discouragement in the health seeking behaviour of pregnant women because it seriously affected their domestic responsibilities. A variety of resource-related factors were shown to affect the health seeking behaviour of pregnant women in rural Tanzania. Thus, accessibility to ANC services was hampered by direct and indirect costs, travel distances and waiting time. Strengthening of user-fee exemption practices and bringing services closer to the users, for example by promoting community-directed control of selected public health services, including IPTp, are urgently needed measures for increasing equity in health services in Tanzania
Emeishan Basalts, SW China: Reappraisal of the formation's type area stratigraphy and a discussion of its significance as a large igneous province
The late Permian Emeishan Basalt Formation of SW China is one of Earth's LIPs (large igneous provinces), yet its basic geology remains poorly documented. Recent work on sections close to the type area in Sichuan Province enable us in part to rectify this. Descriptions of the formation and associated units at two areas, one on the lower flanks of Mt Emei and another from a series of outercrops in Ebian County, 50-70 km to the SW, are presented. The basalt pile is 180-270 m thick and in both areas comprises 12 flows that were erupted in relatively quick succession. It rests conformably upon shallow-marine limestones/lignites suggesting emplacement close to sea level. The upper half of the youngest basalt was intensively weathered, but not eroded, prior to it being conformably succeeded by complex body of rocks c. 30 m thick, that includes thin basalts, pyroclastic rocks, tuffs and organic-rich terrestrial sediments. This unit, which has previously been described as a sedimentary package, presumably because intense weathering has obscured the primary lithological fabric in key outcrops, is considered to mark the volcanic waning phase. Uppermost Permian and Triassic terrestrial sediments conformably overlie the terminal volcanic rocks. The sub-regional stratigraphy is compared, as best it can be, with that described from two sections 400 km to the SE; one section matches reasonably well, the other does not, indicating that regional correlations need to be developed carefully. The information is discussed in the context of LIP generator models; several key features of the Emeishan Basalt terrain are at odds with those commonly encountered in LIP's. The most important conclusion is that the unit marks a prematurely terminated system in which full bloodied rifting leading to the development of an ocean basin never started.published_or_final_versio
Emeishan Basalts (SW China) and the 'end-Guadalupian' crisis: magnetobiostratigraphic constraints
A magnetostratigraphic investigation of the Permian Emeishan LIP (large igneous province) was carried out on a composite section in Ebian County, close to the type area in Sichuan, SW China. The main succession of twelve flows (175 m thick) carries a normal polarity whilst the one reliable site from the overlying 30 m thick volcanic waning sequence is marked by a reverse polarity. The data enable a correlation to be proposed with an Emeishan Basalt sequence in western Guizhou, c. 400 km to the SE. From our knowledge of the geomagnetic field's reversal behaviour during the Permian, it suggests that the main lava pile along the eastern half of the Emeishan Basalt outcrop belt was erupted within a half to one million years. Using magnetobiostratigraphic data from the adjacent South China platform, the normal polarity magnetozone is correlated with the normal polarity chron associated with the upper part of the Maokou Limestones. Constrained by conodont data, the main Emei Basalts appear to be at least two biozones older (1-1.5 Ma) than the Mid-Late Permian boundary. It is possible, however, that the Emei Basalt waning zone sequence, which represents an explosive volcanic phase, might be coeval with the 'end-Guadalupian' biotic crisis. Thus arguments implicating Emei Basalt volcanism as the causal mechanism behind this major global event have to accommodate the new relative-age constraints.published_or_final_versio
Dyslexia detection from EEG signals using SSA component correlation and Convolutional Neural Networks
Objective dyslexia diagnosis is not a straighforward task since it is
traditionally performed by means of the intepretation of different behavioural
tests. Moreover, these tests are only applicable to readers. This way, early
diagnosis requires the use of specific tasks not only related to reading. Thus,
the use of Electroencephalography (EEG) constitutes an alternative for an
objective and early diagnosis that can be used with pre-readers. In this way,
the extraction of relevant features in EEG signals results crucial for
classification. However, the identification of the most relevant features is
not straighforward, and predefined statistics in the time or frequency domain
are not always discriminant enough. On the other hand, classical processing of
EEG signals based on extracting EEG bands frequency descriptors, usually make
some assumptions on the raw signals that could cause indormation loosing. In
this work we propose an alternative for analysis in the frequency domain based
on Singluar Spectrum Analysis (SSA) to split the raw signal into components
representing different oscillatory modes. Moreover, correlation matrices
obtained for each component among EEG channels are classfied using a
Convolutional Neural network.Comment: 11 pages, 7 figures. Submitted to conferenc
Clams on stilts: a phytoplankton bioassay investigating effects of wastewater effluent amendments and Corbicula fluminea grazing
Shallow-water habitats are being restored in the Sacramento-San Joaquin River Delta with the goal of enhancing phytoplankton production and food availability for higher trophic levels. However, elevated grazing pressure from the non-native freshwater clam Corbicula fluminea and localized depletions of dissolved inorganic nitrogen may limit phytoplankton biomass accumulation in restored habitats. To evaluate interactions between nutrients and grazing on phytoplankton productivity and biomass accumulation, Sacramento River water high or low in phytoplankton biomass was amended with wastewater effluent, presence of C. fluminea, or both, in 48 h in situ incubations. We measured changes in chl a concentration, phytoplankton community composition, and photosynthetic efficiency as well as carbon and nitrogen uptake rates as indicators of phytoplankton responses. Diatoms dominated phytoplankton communities before and after incubation. Chl a concentrations increased 0.7 and 7.4 times in the high and low phytoplankton biomass controls, respectively, and 4.5 and 14 times in the high and low phytoplankton biomass effluent-added treatments, respectively. In the clam treatments, chl a accumulation was suppressed to near zero regardless of effluent additions or initial phytoplankton biomass. In treatments with clams and effluent combined, phytoplankton photosynthetic efficiency was nearly 50% lower than in the effluent-only treatments, suggesting phytoplankton were stressed in the presence of clams. This experiment demonstrated that the presence of clams can prevent the accumulation of phytoplankton biomass, both directly by clam filtering and indirectly by depressing phytoplankton photosynthetic efficiency and rate of growth. We recommend that future wetland restoration projects promoting increased phytoplankton biomass assess clam settlement likelihood as well as nutrient availability
FEL research and development at STFC Daresbury laboratory
In this paper we present an overview of current and proposed FEL developments at STFC Daresbury Laboratory in the UK. We discuss progress on the ALICE IR-FEL since first lasing in October 2010, covering the optimisation of the FEL performance, progress on the demonstration of a single shot cross correlation experiment and the results obtained so far with a Scanning Near-Field Optical Microscopy beamline. We discuss a proposal for a 250 MeV single pass FEL test facility named CLARA to be built at Daresbury and dedicated to research for future light source applications. Finally we present a brief overview of other recent research highlights
Impact of Climate Change on the Hydrology of the Upper Awash River Basin, Ethiopia
This study investigated the impacts of climate change on the hydrology of the Upper Awash Basin, Ethiopia. A soil and water assessment tool (SWAT) model was calibrated and validated against observed streamflow using SWAT CUP. The MannâKendall trend test (MK) was used to assess climate trends. Meteorological drought (SPEI) and hydrological drought (SDI) were also investigated. Based on the ensemble mean of five global climate models (GCMs), projected increases in mean annual maximum temperature over the period 2015â2100 (compared with a 1983â2014 baseline) range from 1.16 to 1.73 °C, while increases in minimum temperature range between 0.79 and 2.53 °C. Increases in mean annual precipitation range from 1.8% at Addis Ababa to 45.5% over the Hombole area. High streamflow (Q5) declines at all stations except Ginchi. Low flows (Q90) also decline with Q90 equaling 0 m3 sâ1 (i.e., 100% reduction) at some gauging stations (Akaki and Hombole) for individual GCMs. The SPEI confirmed a significant drought trend in the past, while the frequency and severity of drought will increase in the future. The basin experienced conditions that varied from modest dry periods to a very severe hydrological drought between 1986 and 2005. The projected SDI ranges from modestly dry to modestly wet conditions. Climate change in the basin would enhance seasonal variations in hydrological conditions. Both precipitation and streamflow will decline in the wet seasons and increase in the dry seasons. These changes are likely to have an impact on agricultural activities and other human demands for water resources throughout the basin and will require the implementation of appropriate mitigation measures
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