494 research outputs found
Extreme geochemical variability through the dunitic transition zone of the Oman ophiolite: Implications for melt/fluid-rock reactions at Moho level beneath oceanic spreading centers
International audience15 The Maqsad area in the Oman ophiolite exposes a >300 m thick dunitic mantle-crust 16 transition zone (DTZ) that developed above a mantle diapir. The Maqsad DTZ is primarily 17 f "p " w h scattered chromite and chromite seams) and 18 " p g " which exhibit a significant lithological variability, including various 19 kinds of clinopyroxene-, plagioclase-, orthopyroxene-, amphibole (hornblende/pargasite)-20 bearing dunites. These minerals are interstitial between olivine grains and their variable 21 abundance and distribution suggest that they crystallized from a percolating melt. Generally 22 studied through in-situ mineral characterization, the whole rock composition of dunites is 23 poorly documented. This study reports on whole rock and minerals major and trace element 24 *Manuscript contents on 79 pure to variably impregnated dunites collected systematically along cross 2
X-ray Properties of Pre--Main-Sequence Stars in the Orion Nebula Cluster with Known Rotation Periods
We re-analyze all archival Chandra/ACIS observations of the Orion Nebula
Cluster (ONC) to study the X-ray properties of a large sample of
pre--main-sequence (PMS) stars with optically determined rotation periods. Our
goal is to elucidate the origins of X-rays in PMS stars by seeking out
connections between the X-rays and the mechanisms most likely driving their
production--rotation and accretion. In our sample X-ray luminosity is
significantly correlated with stellar rotation, in the sense of decreasing
Lx/Lbol with more rapid rotation, suggesting that these stars are in the
"super-saturated" regime of the rotation-activity relationship. However, we
also find that stars with optical rotation periods are significantly biased to
high Lx. This is not the result of magnitude bias in the optical
rotation-period sample but rather to the diminishingly small amplitude of
optical variations in stars with low Lx. Evidently, there exists in the ONC a
population of stars whose rotation periods are unknown and that possess lower
average X-ray luminosities than those of stars with known rotation periods.
These stars may sample the linear regime of the rotation-activity relationship.
Accretion also manifests itself in X-rays, though in a somewhat
counterintuitive fashion: While stars with spectroscopic signatures of
accretion show harder X-ray spectra than non-accretors, they show lower X-ray
luminosities and no enhancement of X-ray variability. We interpret these
findings in terms of a common origin for the X-ray emission observed from both
accreting and non-accreting stars, with the X-rays from accreting stars simply
being attenuated by magnetospheric accretion columns. This suggests that X-rays
from PMS stars have their origins primarily in chromospheres, not accretion.Comment: Accepted by the Astronomical Journal. 43 pages, 16 figure
Disparities in breast cancer mortality trends between 30 European countries: retrospective trend analysis of WHO mortality database
Objective To examine changes in temporal trends in breast cancer mortality in women living in 30 European countries
Synchrony, metastability, dynamic integration, and competition in the spontaneous functional connectivity of the human brain
Available online 3 June 2019.The human brain is functionally organized into large-scale neural networks that are dynamically interconnected. Multiple short-lived states of resting-state functional connectivity (rsFC) identified transiently synchronized networks and cross-network integration. However, little is known about the way brain couplings covary as rsFC states wax and wane. In this magnetoencephalography study, we explore the synchronization structure among the spontaneous interactions of well-known resting-state networks (RSNs). To do so, we extracted modes of dynamic coupling that reflect rsFC synchrony and analyzed their spatio-temporal features. These modes identified transient, sporadic rsFC changes characterized by the widespread integration of RSNs across the brain, most prominently in the ÎČ band. This is in line with the metastable rsFC state model of resting-state dynamics, wherein our modes fit as state transition processes. Furthermore, the default-mode network (DMN) stood out as being structured into competitive cross-network couplings with widespread DMN-RSN interactions, especially among the ÎČ-band modes. These results substantiate the theory that the DMN is a core network enabling dynamic global brain integration in the ÎČ band.This work was supported by the Action de Recherche Concert ee (ARC
Consolidation 2015â2019, âCharacterization of the electrophysiological
bases, the temporal dynamics and the functional relevance of resting state
networkâ attributed to X.D.T.) and by the research convention âLes Voies
du Savoirâ (Fonds Erasme, Brussels, Belgium). M.B. benefited from the
program Attract of Innoviris (grant 2015-BB2B-10), the Spanish Ministry
of Economy and Competitiveness (grant PSI2016-77175-P), and theMarie
SkĆodowska-Curie Action of the European Commission (grant 743562).
M.V.G. and G.N.were supported by the Fonds Erasme. N.C. benefited from
a research grant from the ARC Consolidation (2014â2017, âCharacterization
of the electrophysiological bases, the temporal dynamics and the
functional relevance of resting state networkâ attributed to X.D.T.) and
from the Fonds Erasme (research convention âLes Voies du Savoirâ).
X.D.T. is Post-doctorate Clinical Master Specialist at the Fonds de la
Recherche Scientifique (F.R.S.-FNRS, Brussels, Belgium). The MEG project
at the CUB â H^opital Erasme is financially supported by the Fonds Erasme
(research convention âLes Voies du Savoirâ)
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Using Whole-Building Electric Load Data in Continuous or Retro-Commissioning
Whole-building electric load data can often reveal problems with building equipment or operations. In this paper, we present methods for analyzing 15-minute-interval electric load data. These methods allow building operators, energy managers, and commissioning agents to better understand a building's electricity consumption over time and to compare it to other buildings, helping them to 'ask the right questions' to discover opportunities for electricity waste elimination, energy efficiency, peak load management, and demand response. For example: Does the building use too much energy at night, or on hot days, or in the early evening? Knowing the answer to questions like these can help with retro-commissioning or continuous commissioning. The methods discussed here can also be used to assess how building energy performance varies with time. Comparing electric load before and after fixing equipment or changing operations can help verify that the fixes have the intended effect on energy consumption. Analysis methods discussed in this paper include: ways to graphically represent electric load data; the definition of various parameters that characterize facility electricity loads; and a regression-based electricity load model that accounts for both time of week and outdoor air temperature. The methods are illustrated by applying them to data from commercial buildings. We demonstrate the ability to recognize changes in building operation, and to quantify changes in energy performance. Some key findings are: 1) Plotting time series electric load data is useful for understanding electricity consumption patterns and changes to those patterns, but results may be misleading if data from different time intervals are not weather-normalized. 2) Parameter plots can highlight key features of electric load data and may be easier to interpret than plots of time series data themselves. 3) A time-of-week indicator variable (as compared to time-of-day and day-of-week indicator variables) improves the accuracy of regression models of electric load. 4) A piecewise linear and continuous outdoor air temperature dependence can be derived without the use of a change-point model (which would add complexity to the modeling algorithm) or assumptions about when structural changes occur (which could introduce inaccuracy). 5) A model that includes time-of-week and temperature dependence can be used for weather normalization and can determine whether the building is unusually temperature-sensitive, which can indicate problems with HVAC operation
Open Automated Demand Response Dynamic Pricing Technologies and Demonstration
This study examines the use of OpenADR communications specification, related data models, technologies, and strategies to send dynamic prices (e.g., real time prices and peak prices) and Time of Use (TOU) rates to commercial and industrial electricity customers. OpenADR v1.0 is a Web services-based flexible, open information model that has been used in California utilities' commercial automated demand response programs since 2007. We find that data models can be used to send real time prices. These same data models can also be used to support peak pricing and TOU rates. We present a data model that can accommodate all three types of rates. For demonstration purposes, the data models were generated from California Independent System Operator's real-time wholesale market prices, and a California utility's dynamic prices and TOU rates. Customers can respond to dynamic prices by either using the actual prices, or prices can be mapped into"operation modes," which can act as inputs to control systems. We present several different methods for mapping actual prices. Some of these methods were implemented in demonstration projects. The study results demonstrate show that OpenADR allows interoperability with existing/future systems/technologies and can be used within related dynamic pricing activities within Smart Grid
Epidemiologic and Environmental Investigation of a Recreational Water Outbreak Caused by Two Genotypes of Cryptosporidium Parvum in Ohio in 2000
In August 2000, the Ohio Department of Health requested assistance to investigate a cryptosporidiosis outbreak with more than 700 clinical case-patients. An epidemiologic and environmental investigation was conducted. Stool specimens, pool water, and sand filter samples were analyzed. A community-based case-control study showed that the main risk factor was swimming in pool A (odds ratio [OR] = 42, 95% confidence interval [CI] = 12.3-144.9). This was supported by results of polymerase chain reaction (PCR) analysis, which showed the presence of both the human and bovine genotypes of Cryptosporidium parvum in case-patients and samples from the filter of pool A. A pool-based case-control study indicated that the highest risk was related to exposure to pool water via the mouth (OR = 5.1, 95% CI = 2.1-12.5) or to pool sprinklers (OR = 2.5, 95% CI = 1.3-4.7). Fecal accidents at the pool were documented. Records indicated that the pool met local health regulations. The outbreak, caused by co-infection with two C. parvum genotypes (human and bovine), underscores the need for concerted action to improve public health policies for recreational water facilities and enhanced education regarding the potential for disease transmission through pools
Glycan shifting on hepatitis C virus (HCV) E2 glycoprotein is a mechanism for escape from broadly neutralizing antibodies
Hepatitis C virus (HCV) infection is a major cause of liver disease and hepatocellular carcinoma. Glycan shielding has been proposed to be a mechanism by which HCV masks broadly neutralizing epitopes on its viral glycoproteins. However, the role of altered glycosylation in HCV resistance to broadly neutralizing antibodies is not fully understood. Here, we have generated potent HCV neutralizing antibodies hu5B3.v3 and MRCT10.v362 that, similar to the previously described AP33 and HCV1, bind to a highly conserved linear epitope on E2. We utilize a combination of in vitro resistance selections using the cell culture infectious HCV and structural analyses to identify mechanisms of HCV resistance to hu5B3.v3 and MRCT10.v362. Ultra deep sequencing from in vitro HCV resistance selection studies identified resistance mutations at asparagine N417 (N417S, N417T and N417G) as early as 5Â days post treatment. Comparison of the glycosylation status of soluble versions of the E2 glycoprotein containing the respective resistance mutations revealed a glycosylation shift from N417 to N415 in the N417S and N417T E2 proteins. The N417G E2 variant was glycosylated neither at residue 415 nor at residue 417 and remained sensitive to MRCT10.v362. Structural analyses of the E2 epitope bound to hu5B3.v3 Fab and MRCT10.v362 Fab using X-ray crystallography confirmed that residue N415 is buried within the antibodyâpeptide interface. Thus, in addition to previously described mutations at N415 that abrogate the ÎČ-hairpin structure of this E2 linear epitope, we identify a second escape mechanism, termed glycan shifting, that decreases the efficacy of broadly neutralizing HCV antibodies
Visual Reasoning with Multi-hop Feature Modulation
International audienceRecent breakthroughs in computer vision and natural language processing have spurred interest in challenging multi-modal tasks such as visual question-answering and visual dialogue. For such tasks, one successful approach is to condition image-based convolutional network computation on language via Feature-wise Linear Modulation (FiLM) layers, i.e., per-channel scaling and shifting. We propose to generate the parameters of FiLM layers going up the hierarchy of a convolutional network in a multi-hop fashion rather than all at once, as in prior work. By alternating between attending to the language input and generating FiLM layer parameters, this approach is better able to scale to settings with longer input sequences such as dialogue. We demonstrate that multi-hop FiLM generation achieves state-of-the-art for the short input sequence task ReferIt-on-par with single-hop FiLM generation-while also significantly outperforming prior state-of-the-art and single-hop FiLM generation on the GuessWhat?! visual dialogue task
Glycolytic and Non-glycolytic Functions of Mycobacterium tuberculosis Fructose-1,6-bisphosphate Aldolase, an Essential Enzyme Produced by Replicating and Non-replicating Bacilli
The search for antituberculosis drugs active against persistent bacilli has led to our interest in metallodependent class II fructose- 1,6-bisphosphate aldolase (FBA-tb), a key enzyme of gluconeogenesis absent from mammalian cells. Knock-out experiments at the fba-tb locus indicated that this gene is required for the growth of Mycobacterium tuberculosis on gluconeogenetic substrates and in glucose-containing medium. Surface labeling and enzymatic activity measurements revealed that this enzyme was exported to the cell surface of M. tuberculosis and produced under various axenic growth conditions including oxygen depletion and hence by non-replicating bacilli. Importantly, FBA-tb was also produced in vivo in the lungs of infected guinea pigs and mice. FBA-tb bound human plasmin(ogen) and protected FBA-tb-bound plasmin from regulation by α 2-antiplasmin, suggestive of an involvement of this enzyme in host/pathogen interactions. The crystal structures of FBA-tb in the native form and in complex with a hydroxamate substrate analog were determined to 2.35- and 1.9-Ă
resolution, respectively. Whereas inhibitor attachment had no effect on the plasminogen binding activity of FBA-tb, it competed with the natural substrate of the enzyme, fructose 1,6-bisphosphate, and substantiated a previously unknown reaction mechanism associated with metallodependent aldolases involving recruitment of the catalytic zinc ion by the substrate upon active site binding. Altogether, our results highlight the potential of FBA-tb as a novel therapeutic target against both replicating and non-replicating bacilli.Fil: Santangelo, MarĂa de la Paz. State University of Colorado - Fort Collins; Estados Unidos. Instituto Nacional de TecnologĂa Agropecuaria. Centro de InvestigaciĂłn en Ciencias Veterinarias y AgronĂłmicas. Instituto de BiotecnologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Gest, Petra M.. State University of Colorado - Fort Collins; Estados UnidosFil: Guerin, Marcelo E.. Universidad del PaĂs Vasco; EspañaFil: Coinçon, Mathieu. University of Montreal; CanadĂĄFil: Pham, Ha. State University of Colorado - Fort Collins; Estados UnidosFil: Ryan, Gavin. State University of Colorado - Fort Collins; Estados UnidosFil: Puckett, Susan E.. Cornell University; Estados UnidosFil: Spencer, John S.. State University of Colorado - Fort Collins; Estados UnidosFil: Gonzalez Juarrero, Mercedes. State University of Colorado - Fort Collins; Estados UnidosFil: Daher, Racha. Universite de Paris XI. Institut de Chimie MolĂ©culaire et des MatĂ©riaux d'Orsay; FranciaFil: Lenaerts, Anne J.. State University of Colorado - Fort Collins; Estados UnidosFil: Schnappinger, Dirk. Cornell University; Estados UnidosFil: Therisod, Michel. Universite de Paris XI. Institut de Chimie MolĂ©culaire et des MatĂ©riaux d'Orsay; FranciaFil: Ehrt, Sabine. Cornell University; Estados UnidosFil: Sygusch, Jurgen. University of Montreal; CanadĂĄFil: Jackson, Mary. State University of Colorado - Fort Collins; Estados Unido
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