7,200 research outputs found
Trajectory design for autonomous underwater vehicles based on ocean model predictions for feature tracking
Trajectory design for Autonomous Underwater Vehicles (AUVs) is of great importance to the oceanographic research community. Intelligent planning is required to maneuver a vehicle to high-valued locations for data collection. We consider the use of ocean model predictions to determine the locations to be visited by an AUV, which then provides near-real time, in situ measurements back to the model to increase the skill of future predictions. The motion planning problem of steering the vehicle between the computed waypoints is not considered here. Our focus is on the algorithm to determine relevant points of interest for a chosen oceanographic feature. This represents a first approach to an end to end autonomous prediction and tasking system for aquatic, mobile sensor networks. We design a sampling plan and present experimental results with AUV retasking in the Southern California Bight (SCB) off the coast of Los Angeles
Two identification tools applied on Mascarene’s corals genera (Xper2) and species (IKBS)
For future biodiversity studies relying on species
identification, environmental officers and researchers will only be left
with monographic descriptions and collections in museums. This is
why a knowledge base on the zooxanthellate scleractinian corals of
the Mascarene Archipelago is being developed. This project offers
results for both biologists/taxonomists and students or MPA-teams.
Two online computer-based applications permit to identify genera
and species. The first identification tool, called Xper², was developed
by LIS (Informatic and Systematics Laboratory) in Paris, and is used
for identifications to genera. The second tool, named IKBS (Iterative
Knowledge Base System), was developed by IREMIA (Institute
for Research in Applied Mathematics and Computer Science) in
La Réunion, and is used for identifications from families to species. The
tools presently work for Astrocoeniidae, Pocilloporidae, Acroporidae
(only Acropora + Isopora), Psammocoridae, Siderastreidae (owns
Psammocoridae as genera), Fungiidae, Poritidae, Faviidae Faviinae,
Faviidae Montastreinae, Mussidae. We plan to start a new phase to
add the last families, fully translate the web site in English and extend
the Xper² identification to all the western Indian Ocean genera
Developing R&D capacity in a primary care trust : use of the R&D culture index
There has traditionally been a low level of engagement of primary care practitioners with research. In the UK, primary care trusts (PCTs) now have some responsibility for the encouragement of research and development in primary care. The aim of this study was to assess the current level of research activity and capacity for research within a PCT. A questionnaire, incorporating a recently developed and validated research and development culture index, was sent to all 572 health care professionals and staff under the auspices of North Tyneside Research PCT. Data analysis used nonparametric tests of association including chi-squared, Mann–Whitney U and Spearman's rank order correlation. There was a 50.3 per cent response rate to the questionnaire. Groups more likely to show an increased capacity for research included those with postgraduate qualifications and those in post for the least time. General practitioners were less likely than other professional groupings to declare personal skills or aptitude for research. The two most important factors thought to contribute towards the development of a culture of R&D were having access to people to support development and changes in professional practice and having access to training and development opportunities. The use of the R&D culture index enabled groups to be identified that may be more research interested and can therefore be targeted to increase research capacity. The R&D culture index could be used by other PCTs wishing to define and develop research capacity in primary care
Two-sample Bayesian Nonparametric Hypothesis Testing
In this article we describe Bayesian nonparametric procedures for two-sample
hypothesis testing. Namely, given two sets of samples
\stackrel{\scriptscriptstyle{iid}}{\s
im} and \stackrel{\scriptscriptstyle{iid}}{\sim},
with unknown, we wish to
evaluate the evidence for the null hypothesis
versus the
alternative . Our
method is based upon a nonparametric P\'{o}lya tree prior centered either
subjectively or using an empirical procedure. We show that the P\'{o}lya tree
prior leads to an analytic expression for the marginal likelihood under the two
hypotheses and hence an explicit measure of the probability of the null
.Comment: Published at http://dx.doi.org/10.1214/14-BA914 in the Bayesian
Analysis (http://projecteuclid.org/euclid.ba) by the International Society of
Bayesian Analysis (http://bayesian.org/
Paleoproterozoic sterol biosynthesis and the rise of oxygen
Natural products preserved in the geological record can function as ‘molecular fossils’, providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45–2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean–atmosphere system
Cloud Computing Resource Management through a Grid Middleware: A Case Study with DIET and Eucalyptus
The Cloud phenomenon is quickly growing towards becoming the de facto standard of Internet Computing, storage and hosting both in industry and academia. The large scalability possibilities offered by Cloud platforms can be harnessed not only for services and applications hosting but also as a raw on-demand computing resource. This paper proposes the use of a Cloud system as a raw computational on-demand resource for a Grid middleware. We illustrate a proof of concept by considering the DIET-Solve Grid middleware and the EUCALYPTUS open-source Cloud platform
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The impact of histopathology and NAB2-STAT6 fusion subtype in classification and grading of meningeal solitary fibrous tumor/hemangiopericytoma.
Meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is a rare tumor with propensity for recurrence and metastasis. Although multiple classification schemes have been proposed, optimal risk stratification remains unclear, and the prognostic impact of fusion status is uncertain. We compared the 2016 WHO CNS tumor grading scheme (CNS-G), a three-tier system based on histopathologic phenotype and mitotic count, to the 2013 WHO soft-tissue counterpart (ST-G), a two-tier system based on mitotic count alone, in a cohort of 133 patients [59 female, 74 male; mean age 54 years (range 20-87)] with meningeal SFT/HPC. Tumors were pathologically confirmed through review of the first tumor resection (n = 97), local recurrence (n = 35), or distant metastasis (n = 1). A STAT6 immunostain showed nuclear expression in 132 cases. NAB2-STAT6 fusion was detected in 99 of 111 successfully tested tumors (89%) including the single STAT6 immunonegative tumor. Tumors were classified by CNS-G as grade 1 (n = 43), 2 (n = 41), or 3 (n = 49), and by ST-G as SFT (n = 84) or malignant SFT (n = 49). Necrosis was present in 16 cases (12%). On follow-up, 42 patients had at least one subsequent recurrence or metastasis (7 metastasis only, 33 recurrence only, 2 patients had both). Twenty-nine patients died. On univariate analysis, necrosis (p = 0.002), CNS-G (p = 0.01), and ST-G (p = 0.004) were associated with recurrence-free (RFS) but not overall survival (OS). NAB2-STAT6 fusion type was not significantly associated with RFS or OS, but was associated with phenotype. A modified ST-G incorporating necrosis showed higher correlation with RFS (p = 0.0006) and remained significant (p = 0.02) when considering only the primary tumors. From our data, mitotic rate and necrosis appear to stratify this family of tumors most accurately and could be incorporated in a future grading scheme
Squeezing in the audio gravitational wave detection band
We demonstrate the generation of broad-band continuous-wave optical squeezing
down to 200Hz using a below threshold optical parametric oscillator (OPO). The
squeezed state phase was controlled using a noise locking technique. We show
that low frequency noise sources, such as seed noise, pump noise and detuning
fluctuations, present in optical parametric amplifiers have negligible effect
on squeezing produced by a below threshold OPO. This low frequency squeezing is
ideal for improving the sensitivity of audio frequency measuring devices such
as gravitational wave detectors.Comment: 5 pages, 6 figure
Kajian Waktu Strangulasi Terhadap Pembungaan Jeruk Pamelo ‘Cikoneng\u27 (Citrus Grandis (L.) Osbeck)
An Assessment Time of Strangulation on Flowering Induction of Pummelo ‘Cikoneng\u27 (Citrus grandis (L.) Osbeck). Field assessment was conducted at Farmer\u27s Field Bantarmara Village, Cisarua, Sumedang region, West Java from August 2007 to May 2008, to determine the effect of different strangulation times on flowering induction of Pummelo during flowering-off season. Three strangulation times (1,2 and 3 months after harvest, MAH) were arranged in randomized complete block design with 6 (six) replications. An assessment results showed that strangulation at 3 MAH effectively induced flowering appearance (83%) and increased numbers of generative shoots, flowering cluster, bud, blooming, fruit formation and fruit setting. On the other hand, all treated plants had higher C/N ration than control. Kajian lapang dilaksanakan di Tanah Petani (TP) Bantarmara, kecamatan Cisarua, kabupaten Sumedang, Jawa Barat dari bulan Agustus 2007 sampai Mei 2008, untuk melihat waktu strangulasi yang tepat untuk menginduksi bunga diluar musim. Tiga waktu strangulasi (1, 2 dan 3 bulan setelah panen, BSP) disusun menurut rancangan acak kelompok dan 6 (enam) ulangan. Hasil kajian menunjukkan bahwa waktu strangulasi 3 BSP cukup efektif menginduksi jumlah muncul bunga (83%), tetapi mempengaruhi jumlah tunas generative, kluster bunga, kuncup bunga, bunga mekar, buah terbentuk dan fruit set masing-masing 32,67; 28,17; 220,00; 143.33; 61,17 dan 39,02%. Di samping itu, rasio C/N daun pada semua perlakuan lebih tinggi dari control
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