The "neutral" community structure of planktonic herbivores, tintinnid ciliates of the microzooplankton, across the SE Tropical Pacific Ocean

International audienceAcross a species-rich area, the SE Pacific Ocean, the community characteristics of a group of planktonic herbivores was assessed. A series of 22 stations between the Marquise Islands (7° S 142° W) and the coast of Chile (35° S 73° W) was sampled during the BIOSOPE cruise in 2004. The relationships between taxonomic diversity, morphological diversity, patterns of tintinnid species assemblage, and phytoplankton abundance were examined. Tintinnid community characteristics were estimated from large volume (20–60 l) discrete depth sampling and phytoplankton were characterized based on HPLC pigment signatures. Across the transect, average water column concentrations of tintinnids ranged from 2–40 cells l-1or 8–40 ng C l-1, and were positively related to chlorophyll a concentrations which varied between 0.07–2 µg l-1. Large numbers of tintinnid taxa were found, 18–41 species per station, yielding a total of 149 species. Among stations, morphological and taxonomic diversity metrics co-varied but were not significantly related to phytoplankton diversity estimated using a pigment-based size-diversity metric. Taxonomic diversity of tintinnids, as H' or Fishers' alpha, was inversely related to chlorophyll concentration and positively to the depth of the chlorophyll maximum layer. For each station, species abundance distributions were compared to geometric, log-series and log-normal distributions. For most stations, the observed distribution most closely matched log-series, coherent with the neutral theory of random colonization from a large species pool. Occurrence rates of species were correlated with average abundance rather than specific characteristics of biomass or lorica oral diameter (mouth) size. Among stations, species richness was correlated with both the variety of mouth sizes (lorica oral diameters) as well as numbers of species per mouth size, also consistent with random colonization

Using Word Mapping Technique to Improve the Students\u27 Speaking Ability on Hortatory Exposition Text at SMAN 3 Merbau

This classroom action research was aimed to find out if Word Mapping technique in Brainstorming can improve the speaking ability of the students on Hortatory Exposition Text at grade XI Science Class 1 of SMAN 3 Merbau. The participants of this research were all of the students grade XI Science Class 1 of SMAN 3 Merbau (28 students).The procedures applied were: (a) explaining the objective of the learning, the teaching material, material, the text type; hortatory exposition, and the steps in using the technique, (b) dividing students into some groups of discussion and the teacher delivered the learning instruments needed such as flip chart and markers, (c) explaining about Hortatory Exposition Text to the students, (d) choosing the topic together, (e) asking asked to work in their group in limited time to generate ideas related to the topic as many as possible, (f) facilitating students in discussion, and (g) presenting the ideas in front of the class. The data were collected by using tests, observation sheets, and field notes. The level of achievement in this research was 70, based on the standard minimum criteria of achievement of English subject in SMAN 3 Merbau. The research finding showed that the implementation of Word Mapping technique could improve students\u27 speaking ability both at the first and second cycle. Based on the data analysis, the students\u27 score improved from 39,66 in the pre-test, to 56,72 in post-test 1, and up to 72,16 in post-test II. Therefore, the implementation of Word Mapping technique could improve students\u27 speaking ability on Hortatory Exposition text at SMAN 3 Merbau

Magnetic nanocomposites at microwave frequencies

Most conventional magnetic materials used in the electronic devices are ferrites, which are composed of micrometer-size grains. But ferrites have small saturation magnetization, therefore the performance at GHz frequencies is rather poor. That is why functionalized nanocomposites comprising magnetic nanoparticles (e.g. Fe, Co) with dimensions ranging from a few nm to 100 nm, and embedded in dielectric matrices (e.g. silicon oxide, aluminium oxide) have a significant potential for the electronics industry. When the size of the nanoparticles is smaller than the critical size for multidomain formation, these nanocomposites can be regarded as an ensemble of particles in single-domain states and the losses (due for example to eddy currents) are expected to be relatively small. Here we review the theory of magnetism in such materials, and we present a novel measurement method used for the characterization of the electromagnetic properties of composites with nanomagnetic insertions. We also present a few experimental results obtained on composites consisting of iron nanoparticles in a dielectric matrix.Comment: 20 pages, 10 figures, 5 table

An Analysis of the Students' Ability in Comprehending Recount Text at the Second Grade of SMP Muhammadiyah 1 Pekanbaru

This research was designed to describe the students' ability in comprehending recount text. The aim was to find out students ability in comprehending the text. This descriptive research took place in SMP Muhammadiyah 1 Pekanbaru from March to April 2015. The sample was 40 students from VIII2 class that took by using cluster random sampling. In collecting the data, there were 30 questions that included in this test. The duration time for doing the test was 40 minutes. The data was analyzed by calculating the students' score individually and finding out the mean score. The students' score classified into four level mastery; they are: poor, poor to average, average to good, and good to excellent. The data was presented by using graphic. Based on the result finding of this research, the students' ability in comprehending recount text at second grade of SMP Muhammadiyah 1 Pekanbaru was in poor to average level. Meanwhile, the mean score of the whole students' scores was 52.6

Electron-beam-induced current at absorber back surfaces of Cu (In,Ga) Se2 thin-film solar cells

The following article appeared in Journal of Applied Physics 115.1 (2014): 014504 and may be found at http://scitation.aip.org/content/aip/journal/jap/115/1/10.1063/1.4858393The present work reports on investigations of the influence of the microstructure on electronic properties of Cu(In,Ga)Se2 (CIGSe) thin-film solar cells. For this purpose, ZnO/CdS/CIGSe stacks of these solar cells were lifted off the Mo-coated glass substrates. The exposed CIGSe backsides of these stacks were investigated by means of electron-beam-induced current (EBIC) and cathodoluminescence (CL) measurements as well as by electron backscattered diffraction (EBSD). EBIC and CL profiles across grain boundaries (GBs), which were identified by EBSD, do not show any significant changes at Σ3 GBs. Across non-Σ3 GBs, on the other hand, the CL signals exhibit local minima with varying peak values, while by means of EBIC, decreased and also increased short-circuit current values are measured. Overall, EBIC and CL signals change across non-Σ3 GBs always differently. This complex situation was found in various CIGSe thin films with different [Ga]/([In]+[Ga]) and [Cu]/([In]+[Ga]) ratios. A part of the EBIC profiles exhibiting reduced signals across non-Σ3 GBs can be approximated by a simple model based on diffusion of generated charge carriers to the GBs.This work was supported in part by the BMU projects comCIGS and comCIGSII. R.C. acknowledges financial support from Spanish MINECO within the program Ramon y Cajal (RYC-2011-08521)

Prevention of venous thromboembolism in acute spontaneous intracerebral haemorrhage: A survey of opinion

INTRODUCTION: People immobilized following acute spontaneous intracerebral haemorrhage (ICH) are at risk of venous thromboembolism (VTE) but the role of short-term prophylactic anticoagulation remains uncertain. We surveyed UK clinical practice and opinion regarding preventing VTE after ICH. PATIENTS AND METHODS: An online survey was sent to stroke healthcare professionals within the United Kingdom and Ireland via a professional society (British and Irish Association of Stroke Physicians (BIASP)). RESULTS: One hundred and twenty-three staff members responded to the survey, of whom 80% were consultant stroke physicians. All responders except one considered the issue to be important or extremely important, but only 5 (4%) were “extremely certain” and 51 (41%) “fairly certain” regarding the optimal treatment approach. Intermittent pneumatic compression (IPC) devices alone were the most used method (in 60%) followed by IPC devices and switching to low molecular weight heparin (LMWH) (in 30%). We identified high levels of uncertainty regarding the role of anticoagulation, and its optimal timing; uncertainty was greater in lobar compared to deep ICH. Most respondents (93%) consider a randomised controlled trial investigating the role of pharmacological VTE prophylaxis after acute ICH as important and would consider participation. DISCUSSION AND CONCLUSION: The optimal method for the prevention of VTE in non-traumatic ICH patients remains an area of clinical uncertainty. Clinical trials assessing short-term anticoagulation in patients after acute ICH would be beneficial in providing evidence to resolve this clinical dilemma

Microscopic origins of performance losses in highly efficient Cu In, Ga Se2 thin film solar cells

Thin film solar cells based on polycrystalline absorbers have reached very high conversion efficiencies of up to 23 25 . In order to elucidate the limiting factors that need to be overcome for even higher efficiency levels, it is essential to investigate microscopic origins of loss mechanisms in these devices. In the present work, a high efficiency 21 without anti reflection coating copper indium gallium diselenide CIGSe solar cell is characterized by means of a correlative microscopy approach and corroborated by means of photoluminescence spectroscopy. The values obtained by the experimental characterization are used as input parameters for two dimensional device simulations, for which a real microstructure was used. It can be shown that electrostatic potential and lifetime fluctuations exhibit no substantial impact on the device performance. In contrast, nonradiative recombination at random grain boundaries can be identified as a significant loss mechanism for CIGSe solar cells, even for devices at a very high performance leve