591 research outputs found
Classification of uranium ore concentrates applying support vector machine to spectrophotometric and textural features
Uranium ore concentrates (UOCs) are produced in the early stages of the nuclear fuel cycle, prior to conversion to uranium hexafluoride. Because of their high uranium content and the large-scale production, UOCs diversion from civilian use and proliferation are potential risks. This implies the necessity to develop methods able to recognise characteristic parameters correlating each UOC powder to its history and origin. Here, a novel methodology is proposed: first the reflectance spectra of 79 commercial UOCs are acquired and clustered by means of Ward\u27s clustering analysis, then classified by Support Vector Machine (SVM). Second, SVM classification is applied to the image textural features extracted with the Grey Level Co-occurrence Matrix (GLCM) and the Angle Measure Technique (AMT) algorithms for powders in two different colour groups. The developed SVM models present good classification quality: a Matthews correlation coefficient (MCC) of 0.95 is obtained for the classification based on colours while macro-F1 is generally greater than 0.81 (MCC larger than 0.75) for the texture-based classification. These results reveal the potentiality of the present automated classification for the scopes of nuclear forensics in the identification of an unknown uranium ore concentrate sample
Value Efficiency Analysis for Incorporating Preference Information in Data Envelopment Analysis
We develop a procedure and the requisite theory for incorporating preference information in a novel way in the efficiency analysis of Decision Making Units. The efficiency of Decision Making Units is defined in the spirit of Data Envelopment Analysis (DEA), complemented with Decision Maker's preference information concerning the desirable structure of inputs and outputs. Our procedure begins by aiding the Decision Maker in searching for the most preferred combination of inputs and outputs of Decision Making Units (for short, Most Preferred Solution) which are efficient in DEA. Then, assuming that the Decision Maker's Most Preferred Solution maximizes his/her underlying (unknown) value function at the moment when the search is terminated, we approximate the indifference contour of the value function at this point with its possible tangent hyperplanes. Value Efficiency scores are then calculated for each Decision Making Unit comparing the inefficient units to units having the same value as the Most Preferred Solution. The resulting Value Efficiency scores are optimistic approximations of the true scores. The procedure and the resulting efficiency scores are immediately applicable to solving practical problems
Factors increase social welfare of the population in the knowledge economy
At present, the knowledge economy plays a very important role. It is the key to competitiveness in the market and is the driving force of enhanced social life of mankind. Improving the welfare conditions of the knowledge economy is a very urgent problem that most countries are particularly interested. This problem mainly be promoted based on the development of cognitive capital
Towards multi-physics description of fuel behaviour for accidental conditions
In the present document, the development of well-structured multi-physics simulation environments to complement fuel performance analysis is presented. The simulation environments are based on information from the sub-channel / reactor scale, i.e., initial and boundary conditions for the fuel pin simulations in off-normal conditions. The environments are developed based on the codes TRANSURANUS, OpenFOAM, SIMMER-III, and BELLA, focused on satisfying the requirements of the code/module to fuel behaviour, with a strong perspective towards the BPJ simulations of concern for the MYRRHA sub-critical core. The results obtained using the multi-physics simulation environments support the design optimization and safety assessment of the MYRRHA fuel pin during normal irradiation and transient scenarios. As well, it will be used in the activity associated with Task 6.2 of the PATRICIA Project, focused on the in-depth, complete analysis of multiple BPJ scenarios, to identify the worst case and hence draw conservative conclusions on the MYRRHA pin safety under irradiation
Converging and diverging burn rates in North American boreal forests from the Little Ice Age to the present
Warning. This article contains terms, descriptions, and opinions used for historical context that may be culturally sensitive for some readers. Background. Understanding drivers of boreal forest dynamics supports adaptation strategies in the context of climate change. Aims. We aimed to understand how burn rates varied since the early 1700s in North American boreal forests. Methods. We used 16 fire-history study sites distributed across such forests and investigated variation in burn rates for the historical period spanning 1700-1990. These were benchmarked against recent burn rates estimated for the modern period spanning 1980-2020 using various data sources. Key results. Burn rates during the historical period for most sites showed a declining trend, particularly during the early to mid 1900s. Compared to the historical period, the modern period showed less variable and lower burn rates across sites. Mean burn rates during the modern period presented divergent trends among eastern versus northwestern sites, with increasing trends in mean burn rates in most northwestern North American sites. Conclusions. The synchronicity of trends suggests that large spatial patterns of atmospheric conditions drove burn rates in addition to regional changes in land use like fire exclusion and suppression. Implications. Low burn rates in eastern Canadian boreal forests may continue unless climate change overrides the capacity to suppress fire.Peer reviewe
Complete results for five years of GNO solar neutrino observations
We report the complete GNO solar neutrino results for the measuring periods
GNO III, GNO II, and GNO I. The result for GNO III (last 15 solar runs) is
[54.3 + 9.9 - 9.3 (stat.)+- 2.3 (syst.)] SNU (1 sigma) or [54.3 + 10.2 - 9.6
(incl. syst.)] SNU (1 sigma) with errors combined. The GNO experiment is now
terminated after altogether 58 solar exposure runs that were performed between
May 20, 1998 and April 9, 2003. The combined result for GNO (I+II+III) is [62.9
+ 5.5 - 5.3 (stat.) +- 2.5 (syst.)] SNU (1 sigma) or [62.9 + 6.0 - 5.9] SNU (1
sigma) with errors combined in quadrature. Overall, gallium based solar
observations at LNGS (first in GALLEX, later in GNO) lasted from May 14, 1991
through April 9, 2003. The joint result from 123 runs in GNO and GALLEX is
[69.3 +- 5.5 (incl. syst.)] SNU (1 sigma). The distribution of the individual
run results is consistent with the hypothesis of a neutrino flux that is
constant in time. Implications from the data in particle- and astrophysics are
reiterated.Comment: 22 pages incl. 9 Figures and 8 Tables. to appear in: Physics Letters
B (accepted April 13, 2005) PACS: 26.65.+t ; 14.60.P
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Suppression of enteroendocrine cell glucagon-like peptide (GLP)-1 release by fat-induced small intestinal ketogenesis: a mechanism targeted by Roux-en-Y gastric bypass surgery but not by preoperative very-low-calorie diet.
OBJECTIVE: Food intake normally stimulates release of satiety and insulin-stimulating intestinal hormones, such as glucagon-like peptide (GLP)-1. This response is blunted in obese insulin resistant subjects, but is rapidly restored following Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised this to be a result of the metabolic changes taking place in the small intestinal mucosa following the anatomical rearrangement after RYGB surgery, and aimed at identifying such mechanisms. DESIGN: Jejunal mucosa biopsies from patients undergoing RYGB surgery were retrieved before and after very-low calorie diet, at time of surgery and 6 months postoperatively. Samples were analysed by global protein expression analysis and Western blotting. Biological functionality of these findings was explored in mice and enteroendocrine cells (EECs) primary mouse jejunal cell cultures. RESULTS: The most prominent change found after RYGB was decreased jejunal expression of the rate-limiting ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGCS), corroborated by decreased ketone body levels. In mice, prolonged high-fat feeding induced the expression of mHMGCS and functional ketogenesis in jejunum. The effect of ketone bodies on gut peptide secretion in EECs showed a ∼40% inhibition of GLP-1 release compared with baseline. CONCLUSION: Intestinal ketogenesis is induced by high-fat diet and inhibited by RYGB surgery. In cell culture, ketone bodies inhibited GLP-1 release from EECs. Thus, we suggest that this may be a mechanism by which RYGB can remove the inhibitory effect of ketone bodies on EECs, thereby restituting the responsiveness of EECs resulting in increased meal-stimulated levels of GLP-1 after surgery.MRC [MRC_MC_UU_12012/3
MRC_MC_UU_12012/5]
Wellcome Trust [106262/Z/14/Z, 106263/Z/14/Z, 100574/Z/12/Z]
Activation of AMP-Activated Protein Kinase by Interleukin-6 in Rat Skeletal Muscle: Association With Changes in cAMP, Energy State, and Endogenous Fuel Mobilization
OBJECTIVE: Interleukin-6 (IL-6) directly activates AMP-activated protein kinase (AMPK) in vivo and in vitro; however, the mechanism by which it does so is unknown. RESEARCH DESIGN AND METHODS: We examined this question in skeletal muscle using an incubated rat extensor digitorum longus (EDL) muscle preparation as a tool. RESULTS: AMPK activation by IL-6 coincided temporally with a nearly threefold increase in the AMP:ATP ratio in the EDL. The effects of IL-6 on both AMPK activity and energy state were inhibited by coincubation with propranolol, suggesting involvement of β-adrenergic signaling. In keeping with this notion, IL-6 concurrently induced a transient increase in cAMP, and its ability to activate AMPK was blocked by the adenyl cyclase inhibitor 2′5′-dideoxyadenosine. In addition, like other β-adrenergic stimuli, IL-6 increased glycogen breakdown and lipolysis in the EDL. Similar effects of IL-6 on AMPK, energy state, and cAMP content were observed in C2C12 myotubes and gastrocnemius muscle in vivo, indicating that they were not unique to the incubated EDL. CONCLUSIONS: These studies demonstrate that IL-6 activates AMPK in skeletal muscle by increasing the concentration of cAMP and, secondarily, the AMP:ATP ratio. They also suggest that substantial increases in IL-6 concentrations, such as those that can result from its synthesis by muscles during exercise, may play a role in the mobilization of fuel stores within skeletal muscle as an added means of restoring energy balance.United States Public Health Service (RO1DK19514, RO1DK067509); Ruth L.
Kirschstein NRSA Postdoctoral Training Grant (HL-07224); Fonds de la Recherche en Santé du Québe
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