691 research outputs found

    The meiofauna distribution in correlation with environmental characteristics in 5 Mekong estuaries, Vietnam

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    Meiofauna assemblages in 5 estuaries of the Mekong river system (Cua Tieu, Cua Dai, Ba Lai, Co Chien and Dinh An) were sampled for community analysis in March 2009, the dry season. The objectives of this research were to provide the first base line survey of meiofauna assemblages in the 5 Mekong estuaries, and to understand how environmental characteristics affect the densities, diversity and structure of the meiofauna. In each estuary, three to four sampling stations were chosen along the salinity gradient from the river mouth to the fresh water part. Besides the meiofauna also sediment- and water column-related environmental characteristics were identified such as dissolved oxygen, pH, salinity, temperature, median grain size, density of coliform bacteria, nutrient and pigment concentrations. Twenty-three major taxa of meiofauna were recorded over the 19 sampling stations. Nematoda, Copepoda, Turbellaria and Oligochaeta dominated with varying densities, but without any clear correlation with the salinity gradient present along the estuaries. The densities of the meiofauna ranged from 105 to 3678 ind.10 cm-2 on average. Nematodes were always dominant with relative abundances ranging from 40-98% of the total meiofauna. Meiofauna densities were significantly correlated with sediment pigment concentrations but also other factors may play a role. Diversity showed a positive correlation with dissolved oxygen in the overlying water. The observed densities of the intertidal meiofauna in the Mekong delta are high compared to other estuaries worldwide

    Nematodes from sandy beaches of Guanabara Bay, Rio de Janeiro, Brazil

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    This work assessed the nematode composition in three sandy beaches located at Guanabara Bay, Rio de Janeiro, Brazil (22°24’ and 22°57’S; 42°33’ and 43°19’W). These microtidal, sheltered sandy beaches (Bica, Bananal and Coqueiros) were surveyed on January and June 2001, during the low tide. Samples were taken using a PVC core of 10cm2. Nematodes were extracted using the sugar-flotation methodology. The sediment of these beaches was mainly composed of sand and showed a variation between medium to very coarse sediments. In total 6312 specimens were identified up to the genus level or when possible to species level. At the three beaches, 62 genera were found, belonging to 25 families and distributed along of 8 orders. Chromadoridae was the most abundant family in terms of genera. All the families found have also been recorded from previously studied beaches. Amongst the genera found, four of them (Deontolaimus, Dracograllus, Phanodermella and Subsphaerolaimus) were for the first time recorded for Brazilian’s coastline. The number of genera occurring on the Guanabara beaches (31 for Bica, 39 for Bananal and 46 for Coqueiros) is more or less similar to another Brazilian sandy beach whereas these values showed higher variation concerning worldwide tropical and non-tropical beaches. The first occurrence of four genera for the Brazilian coastline suggest the possibility to discover new species in this bay, therefore to the need for further development of nematode taxonomy in Brazil

    Integrated atomic quantum technologies in demanding environments: Development and qualification of miniaturized optical setups and integration technologies for UHV and space operation

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    Employing compact quantum sensors in field or in space (e.g., small satellites) implies demanding requirements on components and integration technologies. Within our work on integrated sensors, we develop miniaturized, ultra-stable optical setups for optical cooling and trapping of cold atomic gases. Besides challenging demands on alignment precision, and thermo-mechanical durability, we specifically address ultra-high vacuum (UHV) compatibility of our integration technologies and optical components. A prototype design of an UHV-compatible, crossed beam optical dipole trap setup and its application within a cold atomic quantum sensor is described. First qualification efforts on adhesive micro-integration technologies are presented. These tests are conducted in application-relevant geometries and material combinations common for micro-integrated optical setups. Adhesive aging will be investigated by thermal cycling or gamma radiation exposure. For vacuum compatibility testing, a versatile UHV testing system is currently being set up, enabling residual gas analysis and measurement of total gas rates down to 5•10-10mbar l/s at a base pressure of 10-11 mbar, exceeding the common ASTM E595 test

    How does the use of digital consulting change the meaning of being a patient and/or a health professional? Lessons from the Long-term Conditions Young People Networked Communication study

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    Background: While studies have examined the impact of digital communication technology on healthcare, there is little exploration of how new models of digital care change the roles and identities of the health professional and patient. The purpose of the current study is to generate multidisciplinary reflections and questions around the use of digital consulting and the way it changes the meaning of being a patient and/or a health professional. Method: We used a large pre-existing qualitative dataset from the Long-term Conditions Young People Networked Communication (LYNC) study which involved interviews with healthcare professionals and a group of 16–24 years patients with long-term physical and mental health conditions. We conducted a three-stage mixed methods analysis. First, using a small sample of interview data from the LYNC study, we identified three key themes to explore in the data and relevant academic literature. Second, in small groups we conducted secondary analysis of samples of patient and health professional LYNC interview data. Third, we ran a series of rapid evidence reviews. Findings: We identified three key themes: workload/flow, impact of increased access to healthcare and vulnerabilities. Both health professionals and patients were 'on duty' in their role more often. Increased access to healthcare introduced more responsibilities to both patients and health professionals. Traditional concepts in medical ethics, confidentiality, empathy, empowerment/power, efficiency and mutual responsibilities are reframed in the context of digital consulting. Conclusions: Our collaboration identified conflicts and constraints in the construction of digital patients and digital clinicians. There is evidence that digital technologies change the nature of a medical consultation and with it the identities and the roles of clinicians and patients which, in turn, calls for a redefinition of traditional concepts of medical ethics. Overall, digital consulting has the potential to significantly reduce costs while maintaining or improving patient care and clinical outcomes. Timely study of digital engagement in the National Health Service is a matter of critical importance

    The jellification of north temperate lakes.

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    Calcium (Ca) concentrations are decreasing in softwater lakes across eastern North America and western Europe. Using long-term contemporary and palaeo-environmental field data, we show that this is precipitating a dramatic change in Canadian lakes: the replacement of previously dominant pelagic herbivores (Ca-rich Daphnia species) by Holopedium glacialis, a jelly-clad, Ca-poor competitor. In some lakes, this transformation is being facilitated by increases in macro-invertebrate predation, both from native (Chaoborus spp.) and introduced (Bythotrephes longimanus) zooplanktivores, to which Holopedium, with its jelly coat, is relatively invulnerable. Greater representation by Holopedium within cladoceran zooplankton communities will reduce nutrient transfer through food webs, given their lower phosphorus content relative to daphniids, and greater absolute abundances may pose long-term problems to water users. The dominance of jelly-clad zooplankton will likely persist while lakewater Ca levels remain low.This work was primarily supported by grants from the Natural Sciences and Engineering Research Council of Canada and funding from the Ontario Ministry of the Environment.This is the accepted manuscript. The final version is available at http://rspb.royalsocietypublishing.org/content/282/1798/20142449

    The Prelude to the Deep Minimum between Solar Cycles 23 and 24: Interplanetary Scintillation Signatures in the Inner Heliosphere

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    Extensive interplanetary scintillation (IPS) observations at 327 MHz obtained between 1983 and 2009 clearly show a steady and significant drop in the turbulence levels in the entire inner heliosphere starting from around ~1995. We believe that this large-scale IPS signature, in the inner heliosphere, coupled with the fact that solar polar fields have also been declining since ~1995, provide a consistent result showing that the buildup to the deepest minimum in 100 years actually began more than a decade earlier.Comment: 9 pages, 4 figures, accepted for publication in Geophysical Research Letters on 28 September 201

    Clinical and genetic spectrum of SCN2A-associated episodic ataxia

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    Background: Pathogenic variants in SCN2A are associated with various neurological disorders including epilepsy, autism spectrum disorder and intellectual disability. Few reports have recently described SCN2A-associated episodic ataxia (EA). Our study identifies its broader clinical and genetic spectrum, and describes pharmacological approaches. Results: We report 21 patients with SCN2A-associated EA, of which 9 are unpublished cases. The large majority of patients present with epileptic seizures (18/21, 86%), often starting within the first three months of life (12/18, 67%). In contrast, onset of episodic ataxia ranged from 10 months to 14 years of age. The frequency of EA episodes ranged from brief, daily events up to 1-2 episodes per year each lasting several weeks. Potential triggers include minor head traumas and sleep deprivation. Cognitive outcome is favorable in most patients with normal or mildly impaired cognitive development in 17/21 patients (81%). No clear genotype-phenotype correlations were identified in this cohort. However, two mutational hotspots were identified, i.e. 7/21 patients (33%) harbor the identical pathogenic variant p.A263V, whereas 5/21 (24%) carry pathogenic variants that affect the S4 segment and its cytoplasmic loop within the domain IV. In addition, we identified six novel pathogenic variants in SCN2A. While acetazolamide was previously reported as beneficial in SCN2A-associated EA in one case, our data show a conflicting response in 8 additional patients treated with acetazolamide: three of them profited from acetazolamide treatment, while 5/8 did not. Conclusions: Our study describes the heterogeneous clinical spectrum of SCN2A-associated EA, identifies two mutational hotspots and shows positive effects of acetazolamide in about 50%. (C) 2019 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.Peer reviewe
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