67,838 research outputs found

    Inflation and inflation uncertainty in the Euro area

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    This paper estimates a time-varying AR-GARCH model of inflation producing measures of inflation uncertainty for the euro area, and investigates the linkages between them in a VAR framework, also allowing for the possible impact of the policy regime change associated with the start of EMU in 1999. The main findings are as follows. Steady-state inflation and inflation uncertainty have declined steadily since the inception of EMU, whilst short-run uncertainty has increased, mainly owing to exogenous shocks. A sequential dummy procedure provides further evidence of a structural break coinciding with the introduction of the euro and resulting in lower long-run uncertainty. It also appears that the direction of causality has been reversed, and that in the euro period the Friedman-Ball link is empirically supported, implying that the ECB can achieve lower inflation uncertainty by lowering the inflation rate

    Shear enhanced heterogeneous nucleation in some Mg- and Al- alloys

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    Intensive shearing was applied to alloy melts at temperatures above their liquidus by using a twinscrew mechanism. The sheared melt was then cast into a TP1 mould for microstructural examination. Alloy melts with or without shearing were also filtered using the Prefil technique developed by N-Tech Ltd in order to analyse oxides and other second phase particles. The experimental results showed a significant grain refinement through enhancement of heterogeneous nucleation. The intensive melt shearing converted oxide films and agglomerates into well dispersed fine particles with a narrow size distribution. It was confirmed that the fine oxide particles can act as potent sites for nucleation during the solidification of the sheared melt. This paper presents the experimental results and theoretical analysis of shear enhanced heterogeneous nucleation during solidification of Mg- and Al-alloys. A multi-step heterogeneous nucleation mechanism has been proposed and discussed

    Anaesthetic challenging in microsurgical flap reconstruction: a systematic review

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    Background: Anaesthetic management for microvascular reconstructive surgery is challenging and clearly affects the risk of major complications such as flap hypo-perfusion. In this systematic review we explore recent (last 7 years) clinical evidences related to perioperative management and anaesthetic controversy of patients undergoing microvascular reconstructive surgery, especially focused on head and neck surgery with free flaps (FF) and breast reconstructive surgery with deep inferior epigastric perforator flap (DIEP-flap). Methods: A literature search of published clinical studies between 2011 and 2018 was conducted, yielding a total of 4307 papers. Only 150 were eligible, according inclusion and exclusion criteria. Results: 62 studies were selected for this review and categorized in 3 groups: preoperative-intraoperative- postoperative anaesthetic management and areas of controversy for patients undergoing head and neck surgery with FF and breast reconstructive surgery with DIEP-flap. Discussion: Anaesthetic management for flap reconstructive surgery remains an open field of interest with limited evidences regarding a standard care. Main components of research currently are: the need to join standard multidisciplinary enhanced recovery pathways, as well as the necessity to develop a standard intraoperative management. In theatre, the recent hemodynamic parameter “Hypotension Probability Indicator” (HPI) is promising: the advantage to predict a drop in the mean arterial pressure can be more effective than a fluid therapy titrated to maintain SVV less than 13%. Prospective studies are necessary to clarify

    Challenging the scientific foundations for an IUCN Red List of Ecosystems

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    The International Union for Conservation of Nature (IUCN) is currently discussing the development of a Red List of Ecosystems (RLE) that would mirror the categories and criteria used to assess the conservation status of species. The suggested scientific foundations for the RLE are being considered by IUCN for adoption as the backbone of the RLE. We identify conceptual and operational weaknesses in the draft RLE approach, the categories, and criteria. While species are relatively well-described units, there is no consistent means to classify ecosystems for assessing conservation status. The proposed RLE is framed mostly around certain features of ecosystems such as broad vegetation or habitat types, and do not consider major global change drivers such as climate change. We discuss technical difficulties with the proposed concept of ecosystem collapse and suggest it is not analogous to species extinction. We highlight the lack of scientific basis for the criteria and thresholds proposed by the RLE, and question the need to adopt the structure of the Red List of Species for an RLE. We suggest that the proposed RLE is open to ambiguous interpretations and uncertain outcomes, and that its practicality and benefit for conservation should be carefully evaluated before final approval

    Exploring Food Detection using CNNs

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    One of the most common critical factors directly related to the cause of a chronic disease is unhealthy diet consumption. In this sense, building an automatic system for food analysis could allow a better understanding of the nutritional information with respect to the food eaten and thus it could help in taking corrective actions in order to consume a better diet. The Computer Vision community has focused its efforts on several areas involved in the visual food analysis such as: food detection, food recognition, food localization, portion estimation, among others. For food detection, the best results evidenced in the state of the art were obtained using Convolutional Neural Network. However, the results of all these different approaches were gotten on different datasets and therefore are not directly comparable. This article proposes an overview of the last advances on food detection and an optimal model based on GoogLeNet Convolutional Neural Network method, principal component analysis, and a support vector machine that outperforms the state of the art on two public food/non-food datasets

    The relative fitness of drug-resistant Mycobacterium tuberculosis: a modelling study of household transmission in Peru.

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    The relative fitness of drug-resistant versus susceptible bacteria in an environment dictates resistance prevalence. Estimates for the relative fitness of resistant Mycobacterium tuberculosis (Mtb) strains are highly heterogeneous and mostly derived from in vitro experiments. Measuring fitness in the field allows us to determine how the environment influences the spread of resistance. We designed a household structured, stochastic mathematical model to estimate the fitness costs associated with multidrug resistance (MDR) carriage in Mtb in Lima, Peru during 2010-2013. By fitting the model to data from a large prospective cohort study of TB disease in household contacts, we estimated the fitness, relative to susceptible strains with a fitness of 1, of MDR-Mtb to be 0.32 (95% credible interval: 0.15-0.62) or 0.38 (0.24-0.61), if only transmission or progression to disease, respectively, was affected. The relative fitness of MDR-Mtb increased to 0.56 (0.42-0.72) when the fitness cost influenced both transmission and progression to disease equally. We found the average relative fitness of MDR-Mtb circulating within households in Lima, Peru during 2010-2013 to be significantly lower than concurrent susceptible Mtb If these fitness levels do not change, then existing TB control programmes are likely to keep MDR-TB prevalence at current levels in Lima, Peru

    Five steps in the evolution from protoplanetary to debris disk

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    The protoplanetary disks of Herbig Ae stars eventually dissipate leaving a tenuous debris disk comprised of planetesimals and dust, as well as possibly gas and planets. This paper uses the properties of 10-20Myr A star debris disks to consider the protoplanetary to debris disk transition. The physical distinction between these two classes is argued to rest on the presence of primordial gas in sufficient quantities to dominate the motion of small dust grains (not the secondary nature of the dust or its level of stirring). This motivates an observational classification based on the dust spectrum, empirically defined so that A star debris disks require fractional excesses <3 at 12um and <2000 at 70um. We also propose a hypothesis to test, that the main sequence planet/planetesimal structures are already in place (but obscured) during the protoplanetary disk phase. This may be only weakly true if planetary architectures change until frozen during disk dispersal, or completely false if planets and planetesimals form during disk dispersal. Five steps in the transition are discussed: (i) carving an inner hole to form a transition disk; (ii) depletion of mm-sized dust in outer disk, noting the importance of determining whether this mass ends up in planetesimals or is collisionally depleted; (iii) final clearing of inner regions, noting that many mechanisms replenish moderate hot dust levels at later phases, and likely also operate in protoplanetary disks; (iv) disappearence of gas, noting recent discoveries of primordial and secondary gas in debris disks that highlight our ignorance and its impending enlightenment by ALMA; (v) formation of ring-like planetesimal structures, noting these are shaped by interactions with planets, and that the location of planetesimals in protoplanetary disks may be unrelated to the dust concentrations therein that are set by gas interactions.The authors are grateful for support from the European Union through ERC grant number 279973.This is the author accepted manuscript. The final version is available via Springer at http://link.springer.com/article/10.1007/s10509-015-2315-6/fulltext.html
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