1,525 research outputs found
Study of an attitude control system for the astronaut maneuvering unit final report, dec. 1963 - jul. 1964
Attitude control system for astronaut maneuvering unit
Using TEI for an Endangered Language Lexical Resource: The NxaÊamxcĂn Database-Dictionary Project
This paper describes the evolution of a lexical resource project for NxaÊamxcĂn, an endangered Salish language, from the projectâs inception in the 1990s, based on legacy materials recorded in the 1960s and 1970s, to its current form as an online database that is transformable into various print and web-based formats for varying uses. We illustrate how we are using TEI P5 for data-encoding and archiving and show that TEI is a mature, reliable, flexible standard which is a valuable tool for lexical and morphological markup and for the production of lexical resources. Lexical resource creation, as is the case with language documentation and description more generally, benefits from portability and thus from conformance to standards (Bird and Simons 2003, Thieberger 2011). This paper therefore also discusses standards-harmonization, focusing on our attempt to achieve interoperability in format and terminology between our database and standards proposed for LMF, RELISH and GOLD. We show that, while it is possible to achieve interoperability, ultimately it is difficult to do so convincingly, thus raising questions about what conformance to standards means in practice.National Foreign Language Resource Cente
Meta-analysis of the efficacy of a single stage laparoscopic management versus two-stage endoscopic management of symptomatic gallstones with common bile duct stones.
Background. The optimal treatment of gallstones with associated common bile duct stones in the laparoscopic era is controversial. Various reviews and decision based algorithms have been published, but the superior treatment modality is unclear. Therefore, a metaanalysis was conducted to compare the two most commonly used treatment strategies.
Methods. A systematic review was conducted to compare single stage laparoscopic cholecystectomy with common bile duct exploration versus a combined endoscopic and laparoscopic treatment. Eligible studies were identified using a search of Medline, Embase, Cochrane and Science Citation Index Expanded databases. Appropriately selected articles were independently reviewed and data was extracted and cross referenced. A meta-analysis was conducted of the pooled trial data to determine difference in outcomes.
Results. A total of seven randomized trials were identified with 746 patients with 366 in the laparoscopic only treatment group and 380 in the combined endoscopic and laparoscopic treatment arms. There was no significant difference in successful bile duct clearance between the two groups (OR 1.23; 95% CI 0.55 to 2.75, P = 0.61). There was no statistical difference in morbidity (RR 1.23; 95% CI 0.92 to 1.66; P = 0.17), mortality (RD -0.00; 95% CI -0.02 to 0.01, P = 0.59) or length of hospital stay (MD -0.31; 95% CI -1.68 to 1.06, P = 0.66). However, there was a statistically significant difference in the duration of procedure in favour of the single stage laparoscopic treatment (MD -6.83; 95% CI -9.59 to -4.07, P \u3c 0.00001).
Conclusion. Both the laparoscopic alone or the combined endoscopic and laparoscopic treatment approaches show comparative efficacy in management of symptomatic gallstones with associated choledocholithiasis
CWRML: representing crop wild relative conservation and use data in XML
Background
Crop wild relatives are wild species that are closely related to crops. They are valuable as potential gene donors for crop improvement and may help to ensure food security for the future. However, they are becoming increasingly threatened in the wild and are inadequately conserved, both in situ and ex situ. Information about the conservation status and utilisation potential of crop wild relatives is diverse and dispersed, and no single agreed standard exists for representing such information; yet, this information is vital to ensure these species are effectively conserved and utilised. The European Community-funded project, European Crop Wild Relative Diversity Assessment and Conservation Forum, determined the minimum information requirements for the conservation and utilisation of crop wild relatives and created the Crop Wild Relative Information System, incorporating an eXtensible Markup Language (XML) schema to aid data sharing and exchange.
Results
Crop Wild Relative Markup Language (CWRML) was developed to represent the data necessary for crop wild relative conservation and ensure that they can be effectively utilised for crop improvement. The schema partitions data into taxon-, site-, and population-specific elements, to allow for integration with other more general conservation biology schemata which may emerge as accepted standards in the future. These elements are composed of sub-elements, which are structured in order to facilitate the use of the schema in a variety of crop wild relative conservation and use contexts. Pre-existing standards for data representation in conservation biology were reviewed and incorporated into the schema as restrictions on element data contents, where appropriate.
Conclusion
CWRML provides a flexible data communication format for representing in situ and ex situ conservation status of individual taxa as well as their utilisation potential. The development of the schema highlights a number of instances where additional standards-development may be valuable, particularly with regard to the representation of population-specific data and utilisation potential. As crop wild relatives are intrinsically no different to other wild plant species there is potential for the inclusion of CWRML data elements in the emerging standards for representation of biodiversity data
Detecting the phase transition in a strongly-interacting Fermi gas by unsupervised machine learning
We study the critical temperature of the superfluid phase transition of
strongly-interacting fermions in the crossover regime between a
Bardeen-Cooper-Schrieffer (BCS) superconductor and a Bose-Einstein condensate
(BEC) of dimers. To this end, we employ the technique of unsupervised machine
learning using an autoencoder neural network which we directly apply to
time-of-flight images of the fermions. We extract the critical temperature of
the phase transition from trend changes in the data distribution revealed in
the latent space of the autoencoder bottleneck.Comment: PRA, in pres
Computer recommendations for an automatic approach and landing system for V/STOL aircraft. Volume 2 - Equations
Automatic approach and landing system for V/STOL aircraf
Machine-learning the phase diagram of a strongly-interacting Fermi gas
We determine the phase diagram of strongly correlated fermions in the
crossover from Bose-Einstein condensates of molecules (BEC) to Cooper pairs of
fermions (BCS) utilizing an artificial neural network. By applying advanced
image recognition techniques to the momentum distribution of the fermions, a
quantity which has been widely considered as featureless for providing
information about the condensed state, we measure the critical temperature and
show that it exhibits a maximum on the bosonic side of the crossover.
Additionally, we back-analyze the trained neural network and demonstrate that
it interprets physically relevant quantities
Uncouplers can shuttle between localized energy-coupling sites during photophosphorylation by chromatophores of Rhodopseudomonas capsulata N22
Low cobalt inventories in the Amundsen and Ross seas driven by high demand for labile cobalt uptake among native phytoplankton communities
Cobalt (Co) is a scarce but essential micronutrient for marine plankton in
the Southern Ocean and coastal Antarctic seas, where dissolved cobalt (dCo)
concentrations can be extremely low. This study presents total dCo and
labile dCo distributions measured via shipboard voltammetry in the Amundsen
Sea, the Ross Sea and Terra Nova Bay during the CICLOPS (Cobalamin and Iron
Co-Limitation of Phytoplankton Species) expedition. A significantly smaller
dCo inventory was observed during the 2017/2018 CICLOPS expedition compared
to two 2005/2006 expeditions to the Ross Sea conducted over a decade
earlier. The dCo inventory loss (âŒâ10â20âpM) was present in
both the surface and deep ocean and was attributed to the loss of labile
dCo, resulting in the near-complete complexation of dCo by strong ligands in
the photic zone. A changing dCo inventory in Antarctic coastal seas could be
driven by the alleviation of iron (Fe) limitation in coastal areas, where the
flux of Fe-rich sediments from melting ice shelves and deep sediment
resuspension may have shifted the region towards vitamin B12 and/or
zinc (Zn) limitation, both of which are likely to increase the demand for Co
among marine plankton. High demand for Zn by phytoplankton can result in
increased Co and cadmium (Cd) uptake because these metals often share the
same metal uptake transporters. This study compared the magnitudes and
ratios of Zn, Cd and Co uptake (Ï) across upper-ocean profiles and
the observed order-of-magnitude uptake trends (ÏZnâ>âÏCdâ>âÏCo) that paralleled the trace metal concentrations in
seawater. High rates of Co and Zn uptake were observed throughout the
region, and the speciation of available Co and Zn appeared to influence
trends in dissolved metalâ:âphosphate stoichiometry and uptake rates over
depth. Multi-year loss of the dCo inventory throughout the water column may
be explained by an increase in Co uptake into particulate organic matter and
subsequently an increased flux of Co into sediments via sinking and burial.
This perturbation of the Southern Ocean Co biogeochemical cycle could signal
changes in the nutrient limitation regimes, phytoplankton bloom composition
and carbon sequestration sink of the Southern Ocean.</p
Globalising assessment: an ethnography of literacy assessment, camels and fast food in the Mongolian Gobi
What happens when standardised literacy assessments travel globally? The paper presents an ethnographic account of adult literacy assessment events in rural Mongolia. It examines the dynamics of literacy assessment in terms of the movement and re-contextualisation of test items as they travel globally and are received locally by Mongolian respondents. The analysis of literacy assessment events is informed by Goodwinâs âparticipation frameworkâ on language as embodied and situated interactive phenomena and by Actor Network Theory. Actor Network Theory (ANT) is applied to examine literacy assessment events as processes of translation shaped by an âassemblageâ of human and non-human actors (including the assessment texts)
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