71 research outputs found
Quick-cast: A method for fast and precise scalable production of fluid-driven elastomeric soft actuators
Fluid-driven elastomeric actuators (FEAs) are among the most popular
actuators in the emerging field of soft robotics. Intrinsically compliant, with
continuum of motion, large strokes, little friction, and high power-to-weight
ratio, they are very similar to biological muscles, and have enabled new
applications in automation, architecture, medicine, and human-robot
interaction. To foster future applications of FEAs, in this paper we present a
new manufacturing method for fast and precise scalable production of complex
FEAs of high quality (leak-free, single-body form, with <0.2 mm precision). The
method is based on 3d moulding and supports elastomers with a wide range of
viscosity, pot life, and Young's modulus. We developed this process for two
different settings: one in laboratory conditions for fast prototyping with 3d
printed moulds and using multi-component liquid elastomers, and the other
process in an industrial setting with 3d moulds micromachined in metal and
applying compression moulding. We demonstrate these methods in fabrication of
up to several tens of two-axis, three-chambered soft actuators, with two types
of chamber walls: cylindrical and corrugated. The actuators are then applied as
motion drivers in kinetic photovoltaic building envelopes
Model discrimination for multicomponent distillation
While rate-based models are available in commercial flowsheet simulation tools, packed distillation columns are still mostly designed based on the equilibrium stage model in combination with HETP values. In order to discriminate between both types of models in a simple way, this article proposes an algorithmic test, based on a geometric criterion for total reflux operation. Substantial differences are illustrated especially for wide-boiling mixtures, while component-specific mass transfer rates either increase or reduce the deviation. The derived results are validated by dedicated experiments
Statistical characterization of strong and mid solar flares and sun EUV rate monitoring with GNSS
The global network of permanent Global Navigation Satellite Systems (GNSS) receivers has become an useful and
affordable way of monitoring the Solar EUV flux rate, especially -for the time being- in the context of Major and
Mid geoeffective intensity Solar Flares (M. Hernandez-Pajares et al., SpaceWeather, doi:10.1029/2012SW000826,
2012). In fact the maturity of this technique (GNSS Solar FLAre Indicator, GSFLAI) has allowed to incorporate
it in operational real-time (RT) conditions, thanks to the availability of global GNSS datastreams from the RT
International GNSS Network (M. Caissy et al, GPS World, June 1, 2012), and performed in the context of the
MONITOR and MONITOR2 ESA-funded projects (Y. Beniguel et al., NAVITEC Proc., 978-1-4673-2011-5
IEEE, 2012).
The main goal of this presentation is to summarize a detailed recent study of the statistical properties of
Solar Flares (E. Monte and M. Hernandez-Pajares, J. Geophys. Res., doi:10.1002/2014JA020206, 2014) by
considering the GNSS proxy of EUV rate (GSFLAI parameter) computed independently each 30 seconds during
the whole last solar cycle. An statistical model has been characterized that explains the empirical results such
as (a) the persistence and presence of bursts of solar flares and (b) their long tail peak values of the solar flux
variation, which can be characterized by: (1) A fractional Brownian model for the long-term dependence, and (2),
a power law distribution for the time series extreme values.
Finally, an update of the Solar Flares’ occurrence during the recent months of Solar Activity, gathered in
RT within MONITOR2 project, will close the paper.Postprint (published version
MONITOR Ionospheric Monitoring System: GNSS performance estimation
MONITOR is a project from the European Space Agency’s GNSS Evolutions Programme started in 2010, dedicated to the collection of data and products during active periods of solar activity for later understanding of the impact of ionospheric effects on EGNOS and Galileo system performance. In the frame of this project several tasks have been achieved, in particular the deployment of a network of scintillation receivers (Novatel + Septentrio + GISMO) mainly at low and high latitudes, the development of a real time Central Archiving and Processing Facility (CAPF) and the development of dedicated processors to generate user oriented outputs for TEC, scintillation, and space weather issues.
This project, in its new phase started in 2014, is moving forward with an improved and updated scope, addressing in addition to general ionospheric monitoring, the generation of dedicated products and reports to EGNOS system evolution, international collaboration in related ionospheric topics including feasibility studies in Africa. The main new features are: an upgraded data archiving system providing improved accessibility, the integration of data from SAGAIE network from French Space Agency, CNES and the exploitation of its data for new products, new station deployment in regions of interest (mainly in West and Central Africa and in high latitudes in Europe), and the upgrade and development of new products allowing better analysis of geophysical conditions during periods of compromised system performance and service. As an example, the Along Arc TEC Rate (AATR index) is computed routinely, as it has proven to be a clear indicator of ionospheric activity that degrades SBAS system performance. In addition, Monitor already produces VTEC maps (obtained using various techniques and algorithms), several space weather indicators including solar flare detection, ROTI maps, indices related to the quality of
measurements and scintillation analysis tools.
This paper focuses on the relationship of an SBAS system (EGNOS, WAAS) to the ionosphere’s variability and will analyse in detail the ionospheric parameters leading to a decrease or compromise of system performance. Several case studies will highlight significant EGNOS events for this purpose. The paper will demonstrate how AATR is able to discriminate availability degradation due to ionospheric events from other effects. The ionosphere scintillation aspects and the last developments of the GISM model will also be addressed for this issue.Peer ReviewedPostprint (author's final draft
Faster HIV-1 Disease Progression among Brazilian Individuals Recently Infected with CXCR4-Utilizing Strains
Introduction: Primary HIV infection is usually caused by R5 viruses, and there is an association between the emergence of CCXR4-utilizing strains and faster disease progression. We characterized HIV-1 from a cohort of recently infected individuals in Brazil, predicted the virus's co-receptor use based on the env genotype and attempted to correlate virus profiles with disease progression. Methods: A total of 72 recently infected HIV patients were recruited based on the Serologic Testing Algorithm for Recent HIV Seroconversion and were followed every three to four months for up to 78 weeks. The HIV-1 V3 region was characterized by sequencing nine to twelve weeks after enrollment. Disease progression was characterized by CD4+ T-cell count decline to levels consistently below 350 cells/mu L. Results: Twelve out of 72 individuals (17%) were predicted to harbor CXCR4-utilizing strains; a baseline CD4,350 was more frequent among these individuals (p = 0.03). Fifty-seven individuals that were predicted to have CCR5-utilizing viruses and 10 individuals having CXCR4-utilizing strains presented with baseline CD4.350; after 78 weeks, 33 individuals with CCR5 strains and one individual with CXCR4 strains had CD4.350 (p = 0.001). There was no association between CD4 decline and demographic characteristics or HIV-1 subtype. Conclusions: Our findings confirm the presence of strains with higher in vitro pathogenicity during early HIV infection, suggesting that even among recently infected individuals, rapid progression may be a consequence of the early emergence of CXCR4-utilizing strains. Characterizing the HIV-1 V3 region by sequencing may be useful in predicting disease progression and guiding treatment initiation decisions.Brazilian Program for STD and AIDSBrazilian Program for STD and AIDSMinistry of Health [914/BRA/3014-UNESCO/Kallas]Ministry of HealthSao Paulo City Health DepartmentSao Paulo City Health Department [2004-0.168.922-7/Kallas]Fundacao de Amparo a Pesquisa do Estado de Sao PauloFundacao de Amparo a Pesquisa do Estado de Sao Paulo [04/15856-9/Diaz]Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Brazilian Ministry of EducationBrazilian Ministry of Educatio
The Crowdsourced Replication Initiative: Investigating Immigration and Social Policy Preferences. Executive Report.
In an era of mass migration, social scientists, populist parties and social movements raise concerns over the future of immigration-destination societies. What impacts does this have on policy and social solidarity? Comparative cross-national research, relying mostly on secondary data, has findings in different directions. There is a threat of selective model reporting and lack of replicability. The heterogeneity of countries obscures attempts to clearly define data-generating models. P-hacking and HARKing lurk among standard research practices in this area.This project employs crowdsourcing to address these issues. It draws on replication, deliberation, meta-analysis and harnessing the power of many minds at once. The Crowdsourced Replication Initiative carries two main goals, (a) to better investigate the linkage between immigration and social policy preferences across countries, and (b) to develop crowdsourcing as a social science method. The Executive Report provides short reviews of the area of social policy preferences and immigration, and the methods and impetus behind crowdsourcing plus a description of the entire project. Three main areas of findings will appear in three papers, that are registered as PAPs or in process
Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals
Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice
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