1,118 research outputs found

    Propuesta alternativa para la inclusión de un criterio de igualación de riesgos en el cálculo del despacho de generación en el mercado de energía eléctrica colombiano

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    In Colombia, the calculation of the generation office is carried out in four stages. In each of them safety and reliability restrictions are added. One of the most important features of dispatch calculation is the inclusion of a risk equalization policy. The dispatch must be such that the expected relative rations in each of the sub-areas of the system are minimal and close to the arithmetic average. This article presents a linear optimization model that allows the generation dispatch to be calculated in a single stage and that includes this risk equalization policy.En Colombia, el cálculo del despacho de generación es realizado en cuatro etapas. En cada una de ellas se adicionan restricciones de seguridad y confiabilidad. Una de las características más importantes del cálculo del despacho es la inclusión de una política de igualación de riesgos. El despacho debe ser tal que los racionamientos relativos esperados en cada una de las sub-áreas del sistema, sean mínimos y cercanos al promedio aritmético. En este artículo se presenta un modelo de optimización lineal que permite calcular el despacho de generación en una sola etapa y que incluye esta política de igualación de riesgos

    Degradation and thermodynamic adsorption process of carbofuran and oxadicyl in a Colombian agricultural soil profile

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    Carbofuran and oxadixyl pesticides are used in Colombia to control pests and fungi, but their mobility through the soil profile is poorly understood. This study showed degradation and adsorption processes of these compounds in a Melanudands soil (0-100 cm) from Colombia using laboratory incubation and the batch equilibrium methods. First-order kinetic models indicated that the degradation rates of carbofuran (0.013-0.006 day-1) and oxadixyl (0.013-0.008 day-1) decreased at deeper soil layers, suggesting that the pesticides were more persistent in the sub-surface (60-100 cm) than in the surface layers (0-40 cm). The thermodynamic approach showed that the adsorption of both pesticides was similar, an exothermic and spontaneous process. The carbofuran and oxadixyl coefficient of distribution (5.8-0.3 L kg-1) and the percentage of adsorption (71.2-11.3%) were very similar in the surface layers (0-40 cm) and decreased with the soil depth. The organic carbon (OC) and clay content showed a positive correlation with the pesticide adsorption throughout the soil profile; therefore, mathematical equations were developed from multiple linear regression models for these soil properties and initial concentration. The equations were important to the estimation of the mobility of the compounds using leaching models under laboratory and field conditions

    Recombinant adenoviral vectors turn on the type I interferon system without inhibition of transgene expression and viral replication

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    Recombinant adenovirus administration gives rise to transgene-independent effects caused by the ability of the vector to activate innate immunity mechanisms. We show that recombinant adenoviruses encoding reporter genes trigger IFN-alpha and IFN-beta transcription from both plasmacytoid and myeloid mouse dendritic cells. Interestingly, IFN-beta and IFN-alpha5 are the predominant transcribed type I IFN genes both in vitro and in vivo. In human peripheral blood leukocytes type I IFNs are induced by adenoviral vectors, with a preponderance of IFN-beta together with IFN-alpha1 and IFN-alpha5 subtypes. Accordingly, functional type I IFN is readily detected in serum samples from human cancer patients who have been treated intratumorally with a recombinant adenovirus encoding thymidine kinase. Despite inducing functional IFN-alpha release in both mice and humans, gene transfer by recombinant adenoviruses is not interfered with by type I IFNs either in vitro or in vivo. Moreover, IFN-alpha does not impair replication of wild-type adenovirus. As a consequence, cancer gene therapy strategies with defective or replicative-competent adenoviruses are not expected to be hampered by the effect of the type I IFNs induced by the vector itself. However, type I IFN might modulate antitumor and antiadenoviral immune responses and thus influence the outcome of gene immunotherapy

    Fiducial marker placement with electromagnetic navigation bronchoscopy: a subgroup analysis of the prospective, multicenter NAVIGATE study

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    Fiducial markers (FMs) help direct stereotactic body radiation therapy (SBRT) and localization for surgical resection in lung cancer management. We report the safety, accuracy, and practice patterns of FM placement utilizing electromagnetic navigation bronchoscopy (ENB). Methods: NAVIGATE is a global, prospective, multicenter, observational cohort study of ENB using the superDimension™ navigation system. This prospectively collected subgroup analysis presents the patient demographics, procedural characteristics, and 1-month outcomes in patients undergoing ENB-guided FM placement. Follow up through 24 months is ongoing. Results: Two-hundred fifty-eight patients from 21 centers in the United States were included. General anesthesia was used in 68.2%. Lesion location was confirmed by radial endobronchial ultrasound in 34.5% of procedures. The median ENB procedure time was 31.0 min. Concurrent lung lesion biopsy was conducted in 82.6% (213/258) of patients. A mean of 2.2 ± 1.7 FMs (median 1.0 FMs) were placed per patient and 99.2% were accurately positioned based on subjective operator assessment. Follow-up imaging showed that 94.1% (239/254) of markers remained in place. The procedure-related pneumothorax rate was 5.4% (14/258) overall and 3.1% (8/258) grade ⩾ 2 based on the Common Terminology Criteria for Adverse Events scale. The procedure-related grade ⩾ 4 respiratory failure rate was 1.6% (4/258). There were no bronchopulmonary hemorrhages. Conclusion: ENB is an accurate and versatile tool to place FMs for SBRT and localization for surgical resection with low complication rates. The ability to perform a biopsy safely in the same procedure can also increase efficiency. The impact of practice pattern variations on therapeutic effectiveness requires further study

    How much can we gain from improved efficiency? An examination of performance of national HIV/AIDS programs and its determinants in low- and middle-income countries

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    <p>Abstract</p> <p>Background</p> <p>The economic downturn exacerbates the inadequacy of resources for combating the worldwide HIV/AIDS pandemic and amplifies the need to improve the efficiency of HIV/AIDS programs.</p> <p>Methods</p> <p>We used data envelopment analysis (DEA) to evaluate efficiency of national HIV/AIDS programs in transforming funding into services and implemented a Tobit model to identify determinants of the efficiency in 68 low- and middle-income countries. We considered the change from the lowest quartile to the average value of a variable a "notable" increase.</p> <p>Results</p> <p>Overall, the average efficiency in implementing HIV/AIDS programs was moderate (49.8%). Program efficiency varied enormously among countries with means by quartile of efficiency of 13.0%, 36.4%, 54.4% and 96.5%. A country's governance, financing mechanisms, and economic and demographic characteristics influence the program efficiency. For example, if countries achieved a notable increase in "voice and accountability" (e.g., greater participation of civil society in policy making), the efficiency of their HIV/AIDS programs would increase by 40.8%. For countries in the lowest quartile of per capita gross national income (GNI), a notable increase in per capita GNI would increase the efficiency of AIDS programs by 45.0%.</p> <p>Conclusions</p> <p>There may be substantial opportunity for improving the efficiency of AIDS services, by providing more services with existing resources. Actions beyond the health sector could be important factors affecting HIV/AIDS service delivery.</p

    After the epidemic: Zika virus projections for Latin America and the Caribbean

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    Background: Zika is one of the most challenging emergent vector-borne diseases, yet its future public health impact remains unclear. Zika was of little public health concern until recent reports of its association with congenital syndromes. By 3 August 2017 ~217,000 Zika cases and ~3,400 cases of associated congenital syndrome were reported in Latin America and the Caribbean. Some modelling exercises suggest that Zika virus infection could become endemic in agreement with recent declarations from the The World Health Organisation. Methodology/Principal findings: We produced high-resolution spatially-explicit projections of Zika cases, associated congenital syndromes and monetary costs for Latin America and the Caribbean now that the epidemic phase of the disease appears to be over. In contrast to previous studies which have adopted a modelling approach to map Zika potential, we project case numbers using a statistical approach based upon reported dengue case data as a Zika surrogate. Our results indicate that ~12.3 (0.7–162.3) million Zika cases could be expected across Latin America and the Caribbean every year, leading to ~64.4 (0.2–5159.3) thousand cases of Guillain-Barré syndrome and ~4.7 (0.0–116.3) thousand cases of microcephaly. The economic burden of these neurological sequelae are estimated to be USD ~2.3 (USD 0–159.3) billion per annum. Conclusions/Significance: Zika is likely to have significant public health consequences across Latin America and the Caribbean in years to come. Our projections inform regional and federal health authorities, offering an opportunity to adapt to this public health challenge

    Dendritic Cells Take up and Present Antigens from Viable and Apoptotic Polymorphonuclear Leukocytes

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    Dendritic cells (DC) are endowed with the ability to cross-present antigens from other cell types to cognate T cells. DC are poised to meet polymorphonuclear leukocytes (PMNs) as a result of being co-attracted by interleukin-8 (IL-8), for instance as produced by tumor cells or infected tissue. Human monocyte-derived and mouse bone marrow-derived DC can readily internalize viable or UV-irradiated PMNs. Such internalization was abrogated at 4°C and partly inhibited by anti-CD18 mAb. In mice, DC which had internalized PMNs containing electroporated ovalbumin (OVA) protein, were able to cross-present the antigen to CD8 (OT-1) and CD4 (OT-2) TCR-transgenic T cells. Moreover, in humans, tumor cell debris is internalized by PMNs and the tumor-cell material can be subsequently taken up from the immunomagnetically re-isolated PMNs by DC. Importantly, if human neutrophils had endocytosed bacteria, they were able to trigger the maturation program of the DC. Moreover, when mouse PMNs with E. coli in their interior are co-injected in the foot pad with DC, many DC loaded with fluorescent material from the PMNs reach draining lymph nodes. Using CT26 (H-2d) mouse tumor cells, it was observed that if tumor cells are intracellularly loaded with OVA protein and UV-irradiated, they become phagocytic prey of H-2d PMNs. If such PMNs, that cannot present antigens to OT-1 T cells, are immunomagnetically re-isolated and phagocytosed by H-2b DC, such DC productively cross-present OVA antigen determinants to OT-1 T cells. Cross-presentation to adoptively transferred OT-1 lymphocytes at draining lymph nodes also take place when OVA-loaded PMNs (H-2d) are coinjected in the footpad of mice with autologous DC (H-2b). In summary, our results indicate that antigens phagocytosed by short-lived PMNs can be in turn internalized and productively cross-presented by DC

    Search for direct top-squark pair production in final states with two leptons in pp collisions at √s = 8TeV with the ATLAS detector

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    A search is presented for direct top-squark pair production in final states with two leptons (electrons or muons) of opposite charge using 20.3 fb−1 of pp collision data at √s = 8 TeV, collected by the ATLAS experiment at the Large Hadron Collider in 2012. No excess over the Standard Model expectation is found. The results are interpreted under the separate assumptions (i) that the top squark decays to a b-quark in addition to an on-shell chargino whose decay occurs via a real or virtual W boson, or (ii) that the top squark decays to a t-quark and the lightest neutralino. A top squark with a mass between 150 GeV and 445 GeV decaying to a b-quark and an on-shell chargino is excluded at 95% confidence level for a top squark mass equal to the chargino mass plus 10 GeV, in the case of a 1 GeV lightest neutralino. Top squarks with masses between 215 (90) GeV and 530 (170) GeV decaying to an on-shell (off-shell) t-quark and a neutralino are excluded at 95% confidence level for a 1 GeV neutralino

    Search for direct top squark pair production in events with a Z boson, b-jets and missing transverse momentum in s √ = 8 TeV pp collisions with the ATLAS detector

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    A search is presented for direct top squark pair production using events with at least two leptons including a same-flavour opposite-sign pair with invariant mass consistent with the Z boson mass, jets tagged as originating from b-quarks and missing transverse momentum. The analysis is performed with proton–proton collision data at s√=8 TeV collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20.3 fb−¹. No excess beyond the Standard Model expectation is observed. Interpretations of the results are provided in models based on the direct pair production of the heavier top squark state (t~2) followed by the decay to the lighter top squark state (t~1) via t~2→Zt~1, and for t~1 pair production in natural gauge-mediated supersymmetry breaking scenarios where the neutralino (χ~10) is the next-to-lightest supersymmetric particle and decays producing a Z boson and a gravitino (G~) via the χ~10→ZG~ process
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