3,321 research outputs found

    Isn’t Limb as Precious as Life?

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    As utilisation of peripheral extra-corporeal life support (ECLS) is becoming clinical routine, its associated complications become more frequent. Distal limb perfusion in femoral cannulation remains one of the Achille’s heels in patients with peripheral ECLS. Unless detected early, limb ischemia may result in loss of limb and sometimes life. A protocol-based approach, precautions during ECLS implantation and explantation procedures and continuous monitoring of the limb during ECLS support are key elements in preventing this complication. Utilisation of a distal limb perfusion cannula helps in prevention as well as management of limb ischemia; however, it may sometimes cause more damage than help. Management and consequence of limb ischemia essentially depends on its severity at the time of detection as well as time of intervention. This chapter offers a brief review of the burden of limb ischemia, means to prevent and approaches to manage it

    Drying of complex suspensions

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    We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy's law correctly estimates both the threshold radius separating these two behaviors, and the rate of large-droplet evacuation. Finally, we use these systems to make novel hierarchical structures.Comment: 4 pages, 4 figure

    Implications of additive manufacturing on supply chain and logistics

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    Additive manufacturing (AM) technology has attracted the interest of industrial professionals and researchers in the last years. This interest lies primarily in understanding the trends, benefits, and implications of AM technology on supply chain (SC) and logistics, as it requires reconfiguring the supply chain based on a distributed manufacturing strategy, closer to the consumer market, with shorter lead times and less raw materials. It still is an emerging field, and needs further study. Therefore, a better understanding of main trends will contribute to the dissemination of knowledge about AM technology and its consolidation. This article seeks to investigate the implications of AM, as an advanced manufacturing model, on SC and logistics. A four-step research method was used to develop a systematic literature review and a bibliometric analysis on the AM implications in SC and logistics. The main implications of AM on SC and logistics were classified in seven key issues gathered as result of the literature review. Additionally, bibliometric study allowed understanding researches major trends in this field. The key aspects highlighted and characterized as major implications of AM on SC and logistic are: supply chain complexity reduction; more flexible logistics and inventory management; better spreading and popularization of mass customization; decentralization of manufacturing; greater design freedom and rapid prototyping; increasing of resource efficiency and sustainability, and the need to have clearly defined legal and safety aspects

    A Systematic Search for Molecular Outflows Toward Candidate Low-Luminosity Protostars and Very Low Luminosity Objects

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    We present a systematic single-dish search for molecular outflows toward a sample of 9 candidate low-luminosity protostars and 30 candidate Very Low Luminosity Objects (VeLLOs; L_int < 0.1 L_sun). The sources are identified using data from the Spitzer Space Telescope catalogued by Dunham et al. toward nearby (D < 400 pc) star forming regions. Each object was observed in 12CO and 13CO J = 2-1 simultaneously using the sideband separating ALMA Band-6 prototype receiver on the Heinrich Hertz Telescope at 30 arcsecond resolution. Using 5-point grid maps we identify five new potential outflow candidates and make on-the-fly maps of the regions surrounding sources in the dense cores B59, L1148, L1228, and L1165. Of these new outflow candidates, only the map of B59 shows a candidate blue outflow lobe associated with a source in our survey. We also present larger and more sensitive maps of the previously detected L673-7 and the L1251-A IRS4 outflows and analyze their properties in comparison to other outflows from VeLLOs. The accretion luminosities derived from the outflow properties of the VeLLOs with detected CO outflows are higher than the observed internal luminosity of the protostars, indicating that these sources likely had higher accretion rates in the past. The known L1251-A IRS3 outflow is detected but not remapped. We do not detect clear, unconfused signatures of red and blue molecular wings toward the other 31 sources in the survey indicating that large-scale, distinct outflows are rare toward this sample of candidate protostars. Several potential outflows are confused with kinematic structure in the surrounding core and cloud. Interferometric imaging is needed to disentangle large-scale molecular cloud kinematics from these potentially weak protostellar outflows.Comment: 42 pages, 19 figures, Accepted for publication in the Astronomical Journa

    Lung Transplantation in Patients with Cystic Fibrosis

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    Cystic fibrosis (CF) is one of the most common indications for lung transplant (LTx) and nearly one-third of the LTx worldwide are performed in people with CF (PwCF). Due to vast developments in diagnostic modalities, antibiotic therapies, and management of associated comorbidities in dedicated and experienced centres, over the past few decades, more PwCF are reaching adulthood than ever before. This has increased the burden on transplant programs particularly in a universal donor shortage scenario. To improve the donor pool a diligent and proactive donor care management, acceptance of marginal organs and utilisation of ex-vivo lung perfusion systems for organ preservation, assessment, and improvement is being advocated widely. LTx is not a readily available therapy and the average waiting time is 18 months in the UK. Therefore, it is essential that PwCF are referred for LTx assessment when their disease is stable, before respiratory deterioration leads to overall deconditioning of the patients. Once listed for LTx, it is crucial to control waiting list mortality by prioritising rapidly deteriorating patients through schemes like the lung allocation score, national urgent and super-urgent waiting lists, and institutional highlighting of deteriorating patients that do not meet other urgent criteria. LTx in PwCF is challenging due to colonisation of the respiratory tract with multi-drug resistant organisms, associated comorbidities such as diabetes, liver disease, gastro-oesophageal reflux, and distal intestinal obstruction syndrome (DIOS) and CF-specific technical difficulties (adhesions due to prior pneumothoraces or pleurodesis, or bronchial collaterals that increase surgical time). Hilar lymphadenopathy and bronchial collaterals may increase surgical time, organ ischemia time, intra and post-operative bleeding, and blood transfusions. Advances in immunosuppression, prophylactic anti-viral and anti-fungal therapies, early ambulation and rigorous physiotherapy, and meticulous postoperative follow up with spirometry, x-rays, and bronchoscopies to detect rejection at the early stage followed by its efficient treatment have helped to improve post-LTx survival in the CF patients. Constant development in the surgical field with adoption of off-pump transplantation, sternal sparing bilateral thoracotomy approach, and utilisation of mechanical circulatory assist as a bridge to transplant and as a support for primary graft failure strives for better outcomes. However, chronic lung allograft dysfunction, chronic refractory infections, malignancies, and CF associated comorbidities remain major determinants of post-LTx long term survival. Despite this, CF patients are often good candidates for re-do LTx with improving survival outcomes. In this chapter, we are compiling the different aspects of LTx in PwCF emphasising the advances in bridge to transplantation, the surgical approach, management of primary graft failure, and immunosuppression as well as complications post-transplant

    Modeling sediment concentrations and loads for two small agricultural watersheds in Prince-Edward-Island (Canada): present conditions and a future scenario.

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    The degradation of soils and its detrimental consequences on aquatic environments is an important research topic in agricultural regions such as Prince Edward Island (PEI, Canada). Enhanced information related to suspended sediments in watercourses can serve as an effective decision-making tool in agricultural land management. This study aims to compare flow, suspended sediment concentrations (SSC), and loads using the Soil and Water Assessment Tool (SWAT) in two watersheds in Prince Edward Island (PEI). The final investigations will focus on the potential variations in hydrological and sedimentary values in the future using a relatively pessimistic climate change scenario. Finally, the projected sediment concentrations and loads will be analyzed, considering their potential impacts on ecosystems. Water level and turbidity were recorded using two water level loggers and two optical backscatter sensors (OBS) deployed in the Tuplin Creek and Spring Valley watersheds. These instruments continuously recorded suspended sediments and flow data from June 2021 to September 2022. The data were used to manually calibrate the hydrological and suspended sediment models. The understanding of sediment loads and the benefits of proposed changes to agricultural practices can be tested with the SWAT model, as it incorporates a land use index that varies spatially and temporally. Calibration and validation of both the hydrological and sediment models were satisfactory, with Kling-Gupta Efficiency coefficients varying between 0.51 and 0.73 and Nash-Sutcliffe coefficients varying between 0.61 and 0.73 respectively, indicating successful simulation of both variables in an agricultural context in spite of relatively short calibration and validation periods. Under the selected climate change scenario (RCP 8.5), daily flows and suspended sediment concentrations were simulated until 2,100, showing a slight increase in the average suspended sediment concentration (CSS). For Tuplin Creek, extremely high sediment peaks (&amp;gt;1,500 mg/L) could become significantly more frequent, potentially causing more frequent and severe ecosystem disturbances according to the simulations

    Photon storage in Lambda-type optically dense atomic media. II. Free-space model

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    In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)], we presented a universal physical picture for describing a wide range of techniques for storage and retrieval of photon wave packets in Lambda-type atomic media in free space, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo based techniques. This universal picture produced an optimal control strategy for photon storage and retrieval applicable to all approaches and yielded identical maximum efficiencies for all of them. In the present paper, we present the full details of this analysis as well some of its extensions, including the discussion of the effects of non-degeneracy of the two lower levels of the Lambda system. The analysis in the present paper is based on the intuition obtained from the study of photon storage in the cavity model in the preceding paper [Gorshkov et al., Phys. Rev. A 76, 033804 (2007)].Comment: 26 pages, 8 figures. V2: significant changes in presentation, new references, higher resolution of figure

    A Nonperturbative Eliasson's Reducibility Theorem

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    This paper is concerned with discrete, one-dimensional Schr\"odinger operators with real analytic potentials and one Diophantine frequency. Using localization and duality we show that almost every point in the spectrum admits a quasi-periodic Bloch wave if the potential is smaller than a certain constant which does not depend on the precise Diophantine conditions. The associated first-order system, a quasi-periodic skew-product, is shown to be reducible for almost all values of the energy. This is a partial nonperturbative generalization of a reducibility theorem by Eliasson. We also extend nonperturbatively the genericity of Cantor spectrum for these Schr\"odinger operators. Finally we prove that in our setting, Cantor spectrum implies the existence of a GδG_\delta-set of energies whose Schr\"odinger cocycle is not reducible to constant coefficients
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