189 research outputs found

    Infecção por riquétsias em carrapatos de aves silvestres em duas ecorregiões da Argentina

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    Several tick-borne Rickettsia species are recognized human pathogens in Argentina. Here we evaluated rickettsial infection in ticks collected on passerine birds during 2011-2012 in two eco-regions of Argentina. The ticks were processed by molecular analysis through polymerase chain reaction (PCR) detection and DNA sequencing of fragments of two rickettsial genes, gltA and ompA. A total of 594 tick specimens (532 larvae and 62 nymphs), representing at least 4 species (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), were evaluated. At least one A. tigrinum larva, collected on Coryphospingus cucullatus in Chaco Seco, was infected with Rickettsia parkeri, whereas at least 12 larvae and 1 nymph of I. pararicinus, collected from Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus and Zonotrichia capensis, were infected with an undescribed Rickettsia agent, genetically related to several rickettsial endosymbionts of ticks of the Ixodes ricinus complex. R. parkeri is a recognized human pathogen in several American countries including Argentina, where a recent study incriminated A. tigrinum as the potential vector of R. parkeri to humans. Birds could play an important role in dispersing R. parkeri-infected A. tigrinum ticks. Additionally, we report for the first time a rickettsial agent infecting I. pararicinus ticks.Algumas espécies de Rickettsia transmitidas por carrapatos são reconhecidos como patógenos humanos na Argentina. Este presente trabalho avaliou a infecção por Rickettsia em carrapatos coletados em aves passeriformes, durante 2011-2012, em duas ecorregiões da Argentina. Os carrapatos foram processados pela reação em cadeia da polimerase (PCR) e sequenciamento de DNA de dois genes de Rickettsia: gltA e ompA. Ao todo, 594 amostras de carrapatos (532 larvas e 62 ninfas), representando pelo menos 4 espécies (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), foram avaliadas. Pelo menos uma larva de A. tigrinum, coletada de Coryphospingus cucullatus no Chaco Seco, estava infectada com Rickettsia parkeri, enquanto pelo menos 12 larvas e 1 ninfa de I. pararicinus, coletadas de Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus e Zonotrichia capensis estavam infectadas com Rickettsia sp., geneticamente relacionada a vários endossimbiontes riquetsiais de carrapatos do complexo Ixodes ricinus. R. parkeri é reconhecidamente um patógeno humano em alguns países americanos, incluindo a Argentina, onde um estudo recente incriminou A. tigrinum como um provável vetor. Aves poderiam desempenhar um papel importante na dispersão de carrapatos A. tigrinum infectados por R. parkeri. Em adição, relata-se pela primeira vez a infecção por Rickettsia em I. pararicinus.Fil: Flores, Fernando Sebastián. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; ArgentinaFil: Borges Costa, Francisco. Universidade de Sao Paulo; BrasilFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Diaz, Luis Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; ArgentinaFil: Labruna, Marcelo Bahía. Universidade de Sao Paulo; Brasi

    Viremia profiles and host competence index for West Nile virus (Flavivirus, Flaviviridae) in three autochthonous birds species from Argentina

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    West Nile virus (WNV) is an emerging Flavivirus dispersing throughout the American continent. It has emerged in the United States as an important medical and veterinary pathogen. It was introduced into Argentina late in 2004 with reported activity in human, wild birds and equines. Field evidence supports the hypothesis of an enzootic transmission cycle between free ranging birds and mosquitoes. The aim of this research was to analyze the role of autochthonous birds as maintenance hosts. Bay-Winged Cowbirds, Picui Ground Doves and Shiny Cowbirds were subcutaneously inoculated with an Argentinean isolate of WNV. Bay-Winged and Shiny Cowbirds developed relatively low mean peak viremias (102.7 and 103.5 PFU/mL serum, respectively). Picui Ground Doves had the highest peak viremia titers of the longest duration [104.8 log PFU/mL serum (range 102.9-6.2; 4-5 days duration)]. No mortality was observed during the study. The reservoir competence index for each species suggests that an infected Picui Ground Dove leads to ten times more infectious mosquitoes than one infected Shiny Cowbird, and that Bay-Winged Cowbird do not represent a source of infectious virus for mosquito vectors. This is the first study carried out in the region regarding the avian host of WNV in Argentina. However, additional studies, including seroprevalence and reservoir competence of resident birds as well as vector competence, are needed to shed light on the ecology of this pathogen in Argentina.Fil: Diaz, Luis Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología "Dr. J. M. Vanella"; Argentina. Ministerio de Ciencia, Tecnología e Innovación Productiva; ArgentinaFil: Flores, Fernando Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología "Dr. J. M. Vanella"; ArgentinaFil: Contigiani de Minio, Marta Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología "Dr. J. M. Vanella"; Argentin

    Effects of Pleistocene climate changes on species ranges and evolutionary processes in the Neotropical Atlantic Forest

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    The effects of global glaciations on the distribution of organisms is an essential element of many diversification models. However, the empirical evidence supporting this idea is mixed, in particular with respect to explaining tropical forest evolution. In the present study, we evaluated the impacts of range shifts associated with Pleistocene global glacial cycles on the evolution of tropical forests. In particular, we tested the predictions: (1) that population genetic structure increases with fragmentation variation between the present and the Last Glacial Maximum (LGM) and also (2) with geographical range instability; and (3) that genetic diversity increases with range stability and (4) decreases with fragmentation variation between periods. To address our predictions, we studied population genetic structures and modelled present and past distributions of 15 Atlantic Forest (AF) endemic birds. Afterwards, we evaluated the relationship of population genetic parameters with metrics of species range shifts between the present and the LGM. We found that geographical ranges of AF birds changed in concert with Pleistocene glacial cycles but, unexpectedly, our findings suggest the novel idea that ranges during glacial maxima were slightly larger on average, as well as equally fragmented and displaced from the interglacial ranges. Our findings suggest that range shifts over the late Pleistocene impacted on the diversification of forest organisms, although they did not show that those range shifts had a strong effect. We found that a combination of fragmentation variation across time, small current range size, and range stability increased population genetic structure. However, neither fragmentation, nor range stability affected genetic diversity. Our study showed that evolutionary responses to range shifts across AF birds have a high variance, which could explain the mixed support given by single-species studies to the action of Pleistocene range shifts on population evolution.Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Calderón, Pablo Luciano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Trujillo Arias, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Flores, Pamela. Universidad Nacional de General Sarmiento; ArgentinaFil: Pessoa, Rodrigo. Universidade Estadual de Montes Claros; BrasilFil: d'Horta, Fernando M.. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Miyaki, Cristina Y.. Universidade de Sao Paulo; Brasi

    Vector competence for West Nile virus and St. Louis encephalitis virus (flavivirus) of three tick species of the genus Amblyomma (Acari: Ixodidae)

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    Many species of Amblyomma ticks are commonly found infesting wild birds in South America, where birds are important hosts for several arboviruses, such as West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). In this study, WNV and SLEV transmission experiments were performed to evaluate the vector competence of three South American tick species: Amblyomma ovale, Amblyomma tigrinum, and Amblyomma tonelliae. Larval and nymphal ticks of each species were allowed to feed on chicks needle inoculated with WNV or SLEV. All three Amblyomma species acquired either WNV or SLEV through larval feeding, with infection rates varying from 3.1% to 100% for WNV and from 0% to 35.7% for SLEV in engorged larvae. Transstadial perpetuation of the viruses was demonstrated in the molted nymphs, with WNV infection rates varying from 0% to 33.7% and SLEV infection rates from 13.6% to 23.8%. Although nymphal ticks also acquired either virus through feeding, transstadial perpetuation to adult ticks was lower, with virus detection in only 3.2% of A. tigrinum and 11.5% of A. tonelliae unfed adult ticks. On the other hand, vector competence for nymphs (exposed to WNV or SLEV through larval feeding) and adult ticks (exposed to WNV or SLEV through larval or nymphal feeding) was null in all cases. Although our results indicate transstadial perpetuation of WNV or SLEV in the three tick species, the ticks were not competent to transmit these agents to susceptible hosts. The role of these ixodid tick species in the epidemiology of WNV and SLEV might be insignificant, even though at least A. ovale and A. tigrinum are frequent bird ticks in Latin America, so the virus could survive winter in the fed larvae. However, future studies are required to determine the implications that this could have, as well as analyze the vector competence of other common bird tick species in South America.Fil: Flores, Fernando Sebastián. Universidad Nacional de Córdoba. Facultad de Medicina; ArgentinaFil: Zanluca, Camila. Instituto Carlos Chagas, Curitiba;Fil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria Eea, Rafaela; ArgentinaFil: Duarte dos Santos, Claudia N.. Instituto Carlos Chagas, Curitiba;Fil: Labruna, Marcelo B.. Universidade de Sao Paulo; BrasilFil: Diaz, Luis Adrian. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina. Universidad Nacional de Córdoba; Argentin

    Museo de Arquitectura de Salamanca, España

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    El edificio del Museo, las colecciones y las muestras que alberga se encuentran intrínsecamente unidos. Definir el carácter de esta relación es el punto de partida de la propuesta. El espacio del Museo como morada de la inspiración, la idea de un lugar para el pensamiento y la reflexión, es algo que se debe plantear cuando uno enfrenta la transformación sustancial de un edificio de estas características. Se rechaza la idea del edificio como un contenedor pasivo. En cambio, se propicia la idea de convertirlo en un espacio contemporáneo, fuertemente conectado con el contexto urbano, capaz de funcionar como un “intercambiador” de información y experiencias diversas. Se trata de crear un espacio abierto y flexible para la celebración de actividades culturales que replantee las relaciones tradicionales entre arquitectura y ciudad y recupere a la vez los valores del edificio original. La reformulación del acceso al Museo crea una instancia de escala urbana peatonal, convirtiéndolo en un catalizador urbano y cultural en simultáneo.Mención honorifica Concurso Internacional de Ideas.Facultad de Arquitectura y Urbanism

    Ticks (Acari: Ixodidae, Argasidae) associated with wild birds in Argentina

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    The aim of this study was to report tick infestations on wild birds from four Phytogeographic Provinces of Argentina. A total of 1085 birds was captured (124 species, 97 genera, 29 families and 13 orders), and ticks were collected from 265 birds (48 species, 40 genera and five orders). A total of 1469 ticks (1102 larvae, 363 nymphs and 4 females) belonging to 15 tick species (Amblyomma calcaratum, Amblyomma dubitatum, Amblyomma nodosum, Amblyomma ovale, Amblyomma parvum, Amblyomma sculptum, Amblyomma tigrinum, Amblyomma triste, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris, Ixodes auritulus sensu lato, Ixodes pararicinus, Ixodes silvanus, Ixodes sp. cf. I. affinis and Ornithodoros sp. cf. O. mimon). Eighty-one new associations between bird species and stages of tick species are detected. The families Thamnophilidae, Turdidae, Thraupidae, Passerellidae, Furnariidae and Troglodytidae were the most prevalent. According to the Phytogeographic Provinces involved in this study, the prevalence of infection for each of them in birds was: (1) Chaco: 28.2% (11 tick species); (2) Yungas: 22.0% (8 tick species); (3) Espinal: 11.1% (2 tick species); and (4) Pampa: 3.9% (1 tick species). This study provided information on the diversity of tick species that parasitize wild birds, the variability of the specific tick-bird associations between the different Phytogeographic Provinces and the relevance of some families of birds as hosts of different tick species.EEA RafaelaFil: Flores, Fernando S. Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Centro de Investigaciones Entomológicas de Córdoba; ArgentinaFil: Flores, Fernando S. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas (IIByT); ArgentinaFil: Saracho Bottero, Maria Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Saracho Bottero, Maria Noelia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Tarragona, Evelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Tarragona, Evelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Sebastian, Patrick. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Sebastian, Patrick. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Copa, Griselda N. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Cátedra de Química Biológica; ArgentinaFil: Guardia, Leonor. Universidad Nacional de Tucumán. Instituto Superior de Entomología; ArgentinaFil: Mangold, Atilio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Mangold, Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IDICAL); ArgentinaFil: Venzal, José Manuel. Universidad de la República. CENUR Litoral Norte. Facultad de Veterinaria. Laboratorio de Vectores y Enfermedades Transmitidas; UruguayFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IDICAL); Argentin

    A laser spectroscopy system with combined absorption, polarization rotation and fluorescence detection to study two photon transitions in atomic rubidium

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    AbstractThe design and construction of an experimental system for studying two photon spectroscopy processes in atomic rubidium is presented. It is designed to measure absorption and polarization rotation induced by any of the two laser beams and also the visible fluorescence that results from decay of the excited states. Two home-built diode lasers are used to produce the optical fields that later interact with room temperature rubidium atoms. Using counterpropagating beams allows velocity selection of the groups of atoms that interact with both laser beams. The system was tested in the 5 S→5 P3/2→5 Dj ladder energy level configuration of atomic rubidium. Blue fluorescence (420nm) that results from decay of the intermediate 6Pj states is filtered and then measured with a photomultiplier tube. Absorption and fluorescence spectra provide mutually complementary information about the interaction between the rubidium atoms and the two optical fields

    Primer reporte de un caso de ehrlichiosis monocítica canina en la provincia de Santa Fe, Argentina

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    La ehrlichiosis monocitica canina (EMC) es una enfermedad causada por la bacteria Ehrlichia canis, de distribución mundial, alta mortalidad en caninos doméstico y síntomas inespecíficos, lo que dificulta su diagnóstico clínico. Ehrlichia canis es transmitida por la garrapata Rhipicephalus sanguineus sensu lato a un hospedador, en Argentina se reconocen dos linajes (tropical y sensu stricto) de dicha especie. El objetivo del presente trabajo es reportar el primer caso confirmado de EMC por E. canis en un canino de la ciudad de Rafaela, Santa Fe, área endémica de R. sanguineus s.s. El 18/02/2019 llegó a la consulta privada un canino con síntomas inespecíficos como hipertermia tarde/noche, depresión, letargia, aplasia, inapetencia y pérdida de peso; más antecedente de parasitismo por garrapatas. La mascota presentaba anemia leve (4.730.000/mm3), enzimas hepáticas aumentadas (AST/ASA/GOT=72 U/l) y esplenomegalia. El test serológico in vitro y PCR para amplificar ADN E. canis fueron positivos, por lo que la mascota recibe tratamiento para EMC con doxiciclina 10 mg/kg/día durante 30 días, antiinflamatorios durante 5 días y protector hepático. A los 60 días de iniciado el tratamiento la mascota recuperó su peso normal y a los 120 días se realiza PCR como monitoreo de la eficacia del tratamiento dando resultado negativo.Fil: Tarragona, Evelina Luisa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Flores, Fernando Sebastián. Laboratorio de Ecología de Enfermedades; ArgentinaFil: Herrera, Cristian Leandro. Clínica Veterinaria Privada; ArgentinaFil: Dalinger, M.. Clínica Veterinaria Privada; ArgentinaFil: Aguirre, Nerina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin

    Effects of Pleistocene climate changes on species ranges and evolutionary processes in the Neotropical Atlantic Forest

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    The effects of global glaciations on the distribution of organisms is an essential element of many diversification models. However, the empirical evidence supporting this idea is mixed, in particular with respect to explaining tropical forest evolution. In the present study, we evaluated the impacts of range shifts associated with Pleistocene global glacial cycles on the evolution of tropical forests. In particular, we tested the predictions: (1) that population genetic structure increases with fragmentation variation between the present and the Last Glacial Maximum (LGM) and also (2) with geographical range instability; and (3) that genetic diversity increases with range stability and (4) decreases with fragmentation variation between periods. To address our predictions, we studied population genetic structures and modelled present and past distributions of 15 Atlantic Forest (AF) endemic birds. Afterwards, we evaluated the relationship of population genetic parameters with metrics of species range shifts between the present and the LGM. We found that geographical ranges of AF birds changed in concert with Pleistocene glacial cycles but, unexpectedly, our findings suggest the novel idea that ranges during glacial maxima were slightly larger on average, as well as equally fragmented and displaced from the interglacial ranges. Our findings suggest that range shifts over the late Pleistocene impacted on the diversification of forest organisms, although they did not show that those range shifts had a strong effect. We found that a combination of fragmentation variation across time, small current range size, and range stability increased population genetic structure. However, neither fragmentation, nor range stability affected genetic diversity. Our study showed that evolutionary responses to range shifts across AF birds have a high variance, which could explain the mixed support given by single-species studies to the action of Pleistocene range shifts on population evolution. © 2016 The Linnean Society of Londo

    JOINSTREAM

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    En el presente trabajo de investigación, se desarrolla el proceso de validación de una idea de negocio llamada JoinStream, la cual consiste en una plataforma que ofrece servicios multi streaming, que agrupa series, películas y cualquier otro material audiovisual ofrecido por las diversas plataformas de streaming en el mercado como Netflix, Disney Plus, Amazon Prime Video, entre otras. Este modelo de negocio está dirigido a hombres y mujeres desde los 18 años de sectores económicos A y B que están interesados en diversas series y películas de varias plataformas de streaming pero que no poseen los ingresos para adquirir más de una suscripción mensual. A lo largo de la investigación, se recurrió a fuentes primarias y secundarias, incluyendo el uso de entrevistas personales y experimentos para conocer las expectativas y necesidades del público objetivo, y validar los elementos que componen el Business Model Canvas del proyecto, obteniendo resultados en su mayoría favorables que demuestran un gran interés del público en la adquisición del servicio. Además, se determinaron los cambios más importantes a realizar en base a la retroalimentación brindada por una muestra representativa del público objetivo. Por último, se realizó el plan financiero del proyecto a 5 años para determinar su viabilidad económica. Para ello se tomó en cuenta los montos de inversión inicial, costos y gastos mensuales, pronóstico de ventas, financiamiento y otros indicadores financieros claves. Se obtiene finalmente un VAN positivo, demostrando que el proyecto es rentable en el largo plazo.In the following research, we develop the process to validate a new business idea named Joinstream, which consists in a multi streaming platform that groups series, movies and any other audiovisual product from many other streaming platform services such as Netflix, Disney Plus, Amazon Prime Video, and others. This business model is aimed at men and women aged 18 years and older from the socioeconomic levels A and B interested in watching series and movies from different streaming platforms but don’t have enough income to expend on more than one monthly subscription. During the investigation, it was made use of primary and secondary sources of research, including the use of personal interviews and experiments to acquire knowledge of expectations and needs of the market segment, and validate all elements from the Business Model Canvas of the project, getting mostly positive results that prove the interest of the public in purchasing the service. In addition, the most important changes to do were obtained by feedback from a representative sample of the market segment. Finally, the financial plan of the project was established for 5 years to determine its economic viability. In order to do that, we considered the amount of initial investment, monthly costs and expenses, sales forecast, funding and other KPI. The final VAN obtained is positive, which demonstrates the project is profitable in the long term.Trabajo de investigació
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