Capacity Choice in a Mixed Duopoly under Price Competition

This paper shows that when firms compete on prices in a mixed duopoly, the public firm chooses over-capacity when products are substitutes and under-capacity when products are complements. The private firm always chooses under-capacity. This result is in contrast with that obtained in the literature assuming quantity competition.Heterogeneous Products

Análisis Preliminar de la Influencia del Proceso de Torneado en la vida a fatiga de la Aleación de Aluminio UNS A92024-T351

Generalmente los elementos estructurales metálicos de las aeronaves se ubican en zonas de carga crítica, en la mayoría de los casos, estos elementos son conformados mediante procesos de mecanizado. La vida a fatiga de estos componentes es una propiedad dinámica muy importante que puede verse intensamente afectada por las condiciones superficiales producidas durante el proceso de mecanizado. En este trabajo se lleva a cabo un primer estudio de la influencia de los parámetros de corte en la resistencia a la fatiga de piezas torneadas de la aleación de aluminio aeronáutico UNS A92024-T351. Se ha prestado especial atención a la relación con el acabado superficial evaluado a partir de la rugosidad media aritmétic

A new perspective of the Alboran Upwelling System reconstruction during the Marine Isotope Stage 11: A high-resolution coccolithophore record

A high-resolution study of the MIS 12/MIS 11 transition and the MIS 11 (430–376 kyr) coccolithophore assemblages at Ocean Drilling Program Site 977 was conducted to reconstruct the palaeoceanographic and climatic changes in the Alboran Sea from the variability in surface water conditions. The nannofossil record was integrated with the planktonic oxygen and carbon stable isotopes, as well as the Uk'37 Sea Surface Temperature (SST) at the studied site during the investigated interval. The coccolithophore primary productivity, reconstructed from the PPP (primary productivity proxy = absolute values of Gephyrocapsa caribbeanica + small Gephyrocapsa group) revealed pronounced fluctuations, that were strongly associated with variations in the intensity of the regional Alboran Upwelling System. The comparison of the nannoplankton record with opal phytolith content for the studied site and the already available pollen record at the nearby Integrated Ocean Drilling Program Site U1385, suggests an association of the upwelling dynamics with the variability of the North Atlantic Oscillation-like (NAO-like) phase. High PPP during positive (+) NAO-like phases is the result of intensified upwelling, owing to the complete development of the surface hydrological structures at the Alboran Sea. This scenario was identified during the MIS 12/MIS 11 transition (428-422 kyr), the late MIS 11c (405-397 kyr), and MIS11 b to MIS 11a (397-376 kyr). Two short-term minima in the PPP and SST were observed during MIS 11 b and were coeval with the North Atlantic Heinrich-type (Ht) events Ht3 (∼390 kyr) and Ht2 (∼384 kyr). Increased abundance of the subpolar Coccolithus pelagicus subsp. pelagicus and Gephyrocapsa muellerae was consistent with the inflow of cold surface waters into the Mediterranean Sea during the Ht events. Lowered PPP during negative (−) NAO-like phases is the result of moderate upwelling by the incomplete development of surface hydrological structures at the Alboran Sea. This scenario is expressed during the early MIS 11c (422-405 kyr). Overall, the results of our study provide evidence of the important role of atmospheric circulation patterns in the North Atlantic region for controlling phytoplankton primary production and oceanographic circulation dynamics in the Western Mediterranean during MIS 11

Innovative Thermal Management Concepts and Material Solutions for Future Space Vehicles

When entering a planetary atmosphere, space vehicles are exposed to extreme thermal loads. To protect the vehicle’s interior, a thermal protection system is required. Future aerospace transportation demands solutions that exceed the performance of current systems and up-to-date material limits. Therefore, new and disruptive solutions must be envisaged to meet those extreme conditions. In the search of new solutions for sharp leading edges of future hypersonic reentry or transport vehicles, the THOR project, composed of eight European organizations (industries, research centers, and universities) and one Japanese Agency (Japan Aerospace Exploration Agency), is actively working on definition, design, implementation, and simulation of new passive and active thermal management solutions and their verification in relevant environments (high-enthalpy facilities). This paper provides an overview of the recent developments on the four concepts that are targeted in the project, applying different physical methodologies: 1) passive cooling using highly conductive carbon-based fibers, 2) passive cooling with intensive internal radiative exchange, 3) active cooling based on convection heat transfer using a ceramic sandwich/thermal protection system with ceramic foams/lattices, and 4) active transpiration cooling of external surfaces. Details on these thermal management concepts, requirements from end users, and test configurations, as well as results from experimental and numerical verification, are given

Evaluation of Clinical and Immunopathological Features of Different Infective Doses of Trypanosoma cruzi in Dogs during the Acute Phase

Infection with Trypanosoma cruzi is a major risk in Latin America, and dogs are believed to be good models for evaluating Chagas disease. Here, we evaluated the clinical and immunopathological alterations developed by mongrel dogs experimentally infected with different infective doses (2,000, 20,000, and 200,000 metacyclic trypomastigotes of Sylvio X10/4 strain kg−1 via intraperitoneal). Clinical and electrocardiographic parameters, as well as antibody production and pathologic lesions were evaluated. All three doses of this strain of T. cruzi induced a similar pattern of infection characterized by cardiac arrhythmias and severe and diffuse myocarditis. Specific anti-T. cruzi IgG indicated seroconversion by day 14 after infection, and IgG levels increased during the period of evaluation. Mortality was observed only in dogs infected with the medium or high parasite doses, but not in the group infected with a low dose of 2,000 parasites kg−1. Infection with a low dose of parasites provides an excellent nonlethal model to evaluate the immunopathology of the acute disease in dogs infected with the Sylvio X10/4 strain of T. cruzi

Uncertain pasts and risk-sensitive futures in sub-Saharan urban transformation

This chapter explores the status and the scope for transition of risk- sensitive and transformative urban development in diverse cities of sub-Saharan Africa. Sub-Saharan Africa is important because of its large proportions of urban populations with high vulnerability and growing exposure to risks. High rates of urban growth pose increasing risks as we go into the future, yet there is also opportunity to reduce risk through integrating risk management into development. However, this opportunity space is often constrained by limited capacities to plan and manage the rapid urbanisation process, particularly in informal settlements. Limited capacities to prevent processes of risk accumulation pose threats to poverty reduction and sustainable development. In this context, there is an increasingly urgent need for squarely recognising and addressing the underlying vulnerabilities of urban populations and their root causes. Transitioning towards such sustainable urban pathways will require the strengthening of capacities and accountability of city authorities and broader governance systems, both formal and informal

Clinicobiological, immunophenotypic, and molecular characteristics of monoclonal CD56‐/+dim chronic natural killer cell large granular lymphocytosis.

Am J Pathol. 2004 Oct;165(4):1117-27. Clinicobiological, immunophenotypic, and molecular characteristics of monoclonal CD56-/+dim chronic natural killer cell large granular lymphocytosis. Lima M, Almeida J, Montero AG, Teixeira Mdos A, Queirós ML, Santos AH, Balanzategui A, Estevinho A, Algueró Mdel C, Barcena P, Fonseca S, Amorim ML, Cabeda JM, Pinho L, Gonzalez M, San Miguel J, Justiça B, Orfão A. Serviço de Hematologia, Unidade de Citometria, Hospital Geral de Santo António, Rua D Manuel II, s/n, 4099-001 Porto, Portugal. [email protected]. Abstract Indolent natural killer (NK) cell lymphoproliferative disorders include a heterogeneous group of patients in whom persistent expansions of mature, typically CD56(+), NK cells in the absence of any clonal marker are present in the peripheral blood. In the present study we report on the clinical, hematological, immunophenotypic, serological, and molecular features of a series of 26 patients with chronic large granular NK cell lymphocytosis, whose NK cells were either CD56(-) or expressed very low levels of CD56 (CD56(-/+dim) NK cells), in the context of an aberrant activation-related mature phenotype and proved to be monoclonal using the human androgen receptor gene polymerase chain reaction-based assay. As normal CD56(+) NK cells, CD56(-/+dim) NK cells were granzyme B(+), CD3(-), TCRalphabeta/gammadelta(-), CD5(-), CD28(-), CD11a(+bright), CD45RA(+bright), CD122(+), and CD25(-) and they showed variable and heterogeneous expression of both CD8 and CD57. Nevertheless, they displayed several unusual immunophenotypic features. Accordingly, besides being CD56(-/+dim), they were CD11b(-/+dim) (heterogeneous), CD7(-/+dim) (heterogeneous), CD2(+) (homogeneous), CD11c(+bright) (homogeneous), and CD38(-/+dim) (heterogeneous). Moreover, CD56(-/+dim) NK cells heterogeneously expressed HLA-DR. In that concerning the expression of killer receptors, CD56(-/+dim) NK cells showed bright and homogeneous CD94 expression, and dim and heterogeneous reactivity for CD161, whereas CD158a and NKB1 expression was variable. From the functional point of view, CD56(-/+dim) showed a typical Th1 pattern of cytokine production (interferon-gamma(+), tumor necrosis factor-alpha(+)). From the clinical point of view, these patients usually had an indolent clinical course, progression into a massive lymphocytosis with lung infiltration leading to death being observed in only one case. Despite this, they frequently had associated cytopenias as well as neoplastic diseases and/or viral infections. In summary, we describe a unique and homogeneous group of monoclonal chronic large granular NK cell lymphocytosis with an aberrant activation-related CD56(-/+dim)/CD11b(-/+dim) phenotype and an indolent clinical course, whose main clinical features are related to concomitant diseases. PMID: 15466379 [PubMed - indexed for MEDLINE]PMCID: PMC161863

Effect of the AlAs capping layer thickness on the structure of InAs/GaAs QD

Recently, very thin AlAs capping layers (CLs) have been proposed as a useful tool to increase the performance of InAs/GaAs quantum dot (QDs) devices. However, the structure of QDs after AlAs deposition remains poorly understood and the mechanisms to explain it are often contradictory. In this work, the structural and compositional changes of InAs QDs using different AlAs CL thicknesses have been studied by state-of-the-art STEM-related techniques. First, the heights and In contents of InAs QDs progressively increase with the CL thickness, demonstrating that the AlAs capping produces a strong shielding effect against the decomposition of QDs. However, QD populations for CL thicknesses above 5 ML split into a bimodal distribution in which smaller lenticular QDs cohabit with bigger truncated pyramids. Second, the actual Al contents around the QDs are well below the nominal design, but increasing for thicker CLs. Its distribution is initially non-uniform, tending to accumulate on the flanks of the QDs to the detriment of the apex. Only for thicknesses above 2 ML the Al contents around the QDs start to be similar to those in the regions between the QDs, behaving as a continuous film without irregularities from 5 ML onwards. © 2021 The Author(s)The work has been co-financed by the Spanish National Research Agency (AEI projects MAT2016-77491-C2-2-R and PID2019-106088RB-C33), Regional Government of Andalusia (project FEDER-UCA18-108319) and the European Regional Development Fund (ERDF)

Influence of the dendron chemical structure on the photophysical properties of bisfluorene-cored dendrimers

A detailed study of the photophysics of a family of bisfluorene-cored dendrimers is reported. Polarized time-resolved fluorescence, singlet-singlet exciton annihilation and fluorescence quantum yield measurements were performed and used to understand how the dendron structure affects the light-emitting properties of the materials. The exciton diffusion rate is similar in all films studied. An increase in the nonradiative deactivation rate by nearly one order of magnitude is observed in films of dendrimers with stilbenyl and carbazolyl based dendrons as compared to solutions, whereas the dendrimers with biphenyl and diphenylethylenyl dendrons showed highly efficient emission (photoluminescence quantum yields of 90%) in both solution and the solid state. The results of the materials that show fluorescence quenching can be explained by the presence of quenching sites at a concentration of just a fraction of a percent of all macromolecules. A possible explanation of this quenching is hole transfer from the emissive chromophore to the dendron in a face-to-face geometry. These results are important for the design of efficient blue emitters for optoelectronic applications. ©2008 American Institute of Physic