2,652 research outputs found

    Pulmonary and cardiac drugs: clinically relevant interactions

    Get PDF
    Chronic heart and lung diseases are very common in the elderly population. The combination of chronic heart failure and chronic obstructive pulmonary disease (COPD) is also common and, according to current guidelines, these patients should be treated for both diseases. In patients with heart failure, beta-blockers are very important drugs because their use is associated with significantly improved morbidity and mortality. These beneficial effects were documented in patients with and without COPD, although theoretically there is a risk for bronchoconstriction, particularly with non-beta1 selective blockers. In COPD patients, long-acting sympathomimetics (LABA) improve lung function, dyspnea, and quality of life and their combination with a beta-blocker makes sense from a pharmacological and a clinical point of view, because any potential arrhythmogenic effects of the LABA will be ameliorated by the beta-blocker. Inhaled tiotropium, a long-acting muscarinic antagonist (LAMA), has been extensively investigated and no safety concerns were reported in terms of cardiac adverse effects. The same applies for the other approved LAMA preparations and LAMA-LABA combinations. Severe COPD causes air-trapping with increasing pressures in the thorax, leading to limitations in blood return into the thorax from the periphery of the body. This causes a decrease in stroke volume and cardiac index and is associated with dyspnea. All these adverse effects can be ameliorated by potent anti-obstructive therapy as recently shown by means of a LABA-LAMA combination

    Pulmonary Vascular Tree Segmentation from Contrast-Enhanced CT Images

    Full text link
    We present a pulmonary vessel segmentation algorithm, which is fast, fully automatic and robust. It uses a coarse segmentation of the airway tree and a left and right lung labeled volume to restrict a vessel enhancement filter, based on an offset medialness function, to the lungs. We show the application of our algorithm on contrast-enhanced CT images, where we derive a clinical parameter to detect pulmonary hypertension (PH) in patients. Results on a dataset of 24 patients show that quantitative indices derived from the segmentation are applicable to distinguish patients with and without PH. Further work-in-progress results are shown on the VESSEL12 challenge dataset, which is composed of non-contrast-enhanced scans, where we range in the midfield of participating contestants.Comment: Part of the OAGM/AAPR 2013 proceedings (1304.1876

    Strong inapproximability of the shortest reset word

    Full text link
    The \v{C}ern\'y conjecture states that every nn-state synchronizing automaton has a reset word of length at most (n1)2(n-1)^2. We study the hardness of finding short reset words. It is known that the exact version of the problem, i.e., finding the shortest reset word, is NP-hard and coNP-hard, and complete for the DP class, and that approximating the length of the shortest reset word within a factor of O(logn)O(\log n) is NP-hard [Gerbush and Heeringa, CIAA'10], even for the binary alphabet [Berlinkov, DLT'13]. We significantly improve on these results by showing that, for every ϵ>0\epsilon>0, it is NP-hard to approximate the length of the shortest reset word within a factor of n1ϵn^{1-\epsilon}. This is essentially tight since a simple O(n)O(n)-approximation algorithm exists.Comment: extended abstract to appear in MFCS 201

    An agent-based model of wood markets: Scenario analysis

    Full text link
    We present an agent-based model of wood markets. The model covers softwood and hardwood markets for sawlogs, energy wood, and industrial wood. Our study region is a mountainous area in Switzerland that is close to the border, and therefore partially depends on the wood markets of the adjacent countries. The wood markets in this study region are characterized by many small-scale wood suppliers, and a mix of private and publicowned forests. The model was developed to investigate the availability of wood in the study region under different market conditions. We defined several scenarios that are relevant to policy makers and analyzed them with a focus on the two most important assortments of wood in the study region, namely, sawlogs softwood and energy wood softwood. The development of the prices and amounts sold in the scenarios are compared to a business-as-usual scenario. The scenarios were designed to investigate i) the influence of intermediaries, ii) the influence of the profit-orientation of forest owners, iii) the influence of the exchange rate, and iv) the consequences of set-asides in the study region. The presented model has a large potential to support the planning of policy measures as it allows capturing emergent phenomena, and thereby facilitates identifying potential consequences of policy measures planned prior to their implementation. This was demonstrated by discussing the scenario findings with respect to Switzerland's forestry policy objective of increasing the harvested amount of wood to the sustainable potential. We showed that a higher profit-orientation of forest owners would be beneficial for this objective, but also revealed potential conflicts of different economic goals

    Economic analysis of afforestation projects for carbon sequestration: a case study in Patagonia, Argentina

    Get PDF
    89 p.La mitigación del calentamiento global en forma eficiente es una de las prioridades de las acciones a escala mundial. Los Mecanismos de Desarrollo Limpio (MDL) del Protocolo de Kioto podrían mitigar el cambio climático y a su vez beneficiar a las comunidades locales. Sin embargo, dada la actual incertidumbre sobre el precio del CO2 para créditos temporales y el alto nivel de costos de transacción, proyectos MDL de pequeña escala podrían no ser factibles. Este estudio aspira a determinar el costo y la rentabilidad de secuestrar carbono por medio de plantaciones de Pinus ponderosa en sitios de calidad medio-alta en el sur de Argentina. La cantidad de certificados de reducción de emisiones (CERs) expedidos se estimó utilizando el método de los créditos temporales (TCER) y el método de créditos a largo plazo (LCER). Por otra parte, los puntos críticos del proyecto para distintas variables, se calcularon como los valores a partir de los cuales los ingresos obtenidos por la venta de CERs cubren los costos de transacción. Los resultados muestran que la producción conjunta - madera y CERs - incrementa la rentabilidad del proyecto comparada con la producción de madera únicamente. Ambos métodos de contabilizar carbono han demostrado casi el mismo funcionamiento, sin embargo, la mayor diferencia surge en la distribución de los pagos en el flujo neto efectivo. Bajo un escenario medio (8,2 €/CER, i=8%), la superficie mínima obtenida para proyectos rentables es de 200 ha usando el método TCER, o 220 ha aplicando el método LCER. Por otra parte, se encontraron ventajas comparativas en el costo de fijación de CO2 a través de plantaciones de pino ponderosa en Patagonia. El valor presente del costo de secuestro de CO2 es 5,3 /tCO2,yelcostodeproduccioˊndeCERses6,2/t CO2, y el costo de producción de CERs es 6,2 /TCER y 8,3 /LCER,siempreavalorpresente.Elusodeunesquemadefinanciamientolocalparadesarrollarcarterasdeproyectospodrıˊaserunaposiblealternativaparareducirelproblemadeescaladelosmismos.Comolaescalatieneunfuerteimpactosobrelarentabilidaddelosproyectos,eˊstospodrıˊanserllevadosacabopormediodelaasociacioˊndepequen~osproductoreseinversores.Enconsecuencia,tantolosriesgoscomolosbeneficiosdelproyectoserıˊancompartidosentresusparticipantesyelatractivodelmismoseverıˊaincrementado.Porlotanto,bajolosescenariosasumidos,pequen~osproyectosdeforestacioˊnenelmarcodelosMDLenPatagonianosoloserıˊanviablessinoquetambieˊnventajosos.SUMMARYThemitigationofglobalwarminginacostefficientwayisoneoftheglobalactionpriorities.CleanDevelopmentMechanismsoftheKyotoProtocolcouldmitigatetheclimatechangeandtobenefitlocalcommunitiesaswell.However,giventhecurrentuncertaintyaboutcarbonpricesfortemporarycreditsandthehighleveloftransactioncosts,CDMforestryprojectsofsmallscalecouldbeunfeasible.ThisstudyaimstodeterminethecostandprofitabilityofsequesteringCO2inPinusponderosaplantationsonaveragetohighqualitysitesintheSouthofArgentina.Thenumberofcertifiedemissionreductions(CERs)tobeissuedisestimatedusingtemporarycredits(TCER)andlongtermcredits(LCER).Furthermore,criticpointsfordifferentvariablesarecalculatedasthevalueswheretherevenuesfromsalesofCERscoverthetransactioncosts.ResultsshowthattheconjointproductiontimberplusCERsalesincreasesprojectsprofitabilitycomparedtotimberproductionalone.Differentaccountingapproachesusedhavealmostthesameperformance,eventhough,themajordifferenceisoriginateinthecashflowpaymentdistribution.Underanaveragescenario(8,2/CER,i=8theminimumsizeachievedforprofitableprojectsis200haor220hausingtheTCERorLCERapproachrespectively.Furthermore,comparativeadvantagesarefoundinthecostsofsequesteringcarbondioxidebyPonderosapineplantationsinPatagonia.Thepresentvalueofcarbonsequestrationcostsis5,3/LCER, siempre a valor presente. El uso de un esquema de financiamiento local para desarrollar carteras de proyectos podría ser una posible alternativa para reducir el problema de escala de los mismos. Como la escala tiene un fuerte impacto sobre la rentabilidad de los proyectos, éstos podrían ser llevados a cabo por medio de la asociación de pequeños productores e inversores. En consecuencia, tanto los riesgos como los beneficios del proyecto serían compartidos entre sus participantes y el atractivo del mismo se vería incrementado. Por lo tanto, bajo los escenarios asumidos, pequeños proyectos de forestación en el marco de los MDL en Patagonia no solo serían viables sino que también ventajosos. SUMMARY The mitigation of global warming in a cost-efficient way is one of the global action priorities. Clean Development Mechanisms of the Kyoto Protocol could mitigate the climate change and to benefit local communities as well. However, given the current uncertainty about carbon prices for temporary credits and the high level of transaction costs, CDM forestry projects of small scale could be unfeasible. This study aims to determine the cost and profitability of sequestering CO2 in Pinus ponderosa plantations on average to high quality sites in the South of Argentina. The number of certified emission reductions (CERs) to be issued is estimated using temporary credits (TCER) and long-term credits (LCER). Furthermore, critic points - for different variables - are calculated as the values where the revenues from sales of CERs cover the transaction costs. Results show that the conjoint production –timber plus CER sales- increases projects profitability compared to timber production alone. Different accounting approaches used have almost the same performance, even though, the major difference is originate in the cash flow payment distribution. Under an average scenario (8,2 €/CER, i=8%), the minimum size achieved for profitable projects is 200 ha or 220 ha using the TCER or LCER approach respectively. Furthermore, comparative advantages are found in the costs of sequestering carbon dioxide by Ponderosa pine plantations in Patagonia. The present value of carbon sequestration costs is 5,3 /t CO2, and the CERs production costs is 6,2 /TCERand8,3/ TCER and 8,3 / LCER, always in present value. Using a local financial scheme to prepare project portfolios could be a possible alternative to cope with project scale. As the area has a strong impact on the project profitability; these could be carried out by the association of small farmers or investors. Consequently, both the risk and the project benefits would be shared among the participants and the attractiveness of the project increased. Therefore, small scale CDM afforestation projects in Patagonia under the scenarios assumed would not only be feasible but also advantageous

    Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

    Get PDF
    GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is an airborne, imaging, infrared Fourier transform spectrometer that applies the limb-imaging technique to perform trace gas and temperature measurements in the Earth's atmosphere with three-dimensional resolution. To ensure the traceability of these measurements to the International Temperature Scale and thereby to an absolute radiance scale, GLORIA carries an on-board calibration system. Basically, it consists of two identical large-area and high-emissivity infrared radiators, which can be continuously and independently operated at two adjustable temperatures in a range from −50 °C to 0 °C during flight. Here we describe the radiometric and thermometric characterization and calibration of the in-flight calibration system at the Reduced Background Calibration Facility of the Physikalisch-Technische Bundesanstalt. This was performed with a standard uncertainty of less than 110 mK. Extensive investigations of the system concerning its absolute radiation temperature and spectral radiance, its temperature homogeneity and its short- and long-term stability are discussed. The traceability chain of these measurements is presented

    Checking Whether an Automaton Is Monotonic Is NP-complete

    Full text link
    An automaton is monotonic if its states can be arranged in a linear order that is preserved by the action of every letter. We prove that the problem of deciding whether a given automaton is monotonic is NP-complete. The same result is obtained for oriented automata, whose states can be arranged in a cyclic order. Moreover, both problems remain hard under the restriction to binary input alphabets.Comment: 13 pages, 4 figures. CIAA 2015. The final publication is available at http://link.springer.com/chapter/10.1007/978-3-319-22360-5_2
    corecore