161 research outputs found

    First record of Mylodontinae (Tardigrada, Mylodontidae) from the Huayquerian (Late Miocene) of Buenos Aires province, Argentina

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    Los Mylodontinae (Xenarthra, Mylodontidae) están bien representados en el Mioceno tardío (Chasiquense-Huayqueriense) y Plioceno (Montehermosense-Chapadmalalense) de Sudamérica (con más de una docena de géneros reconocidos). Para el Piso/Edad Huayqueriense de Argentina la diversidad es alta (casi diez especies documentadas). Sin embargo, no hay registros certeros de la subfamilia en la provincia de Buenos Aires durante el Huayqueriense. En este trabajo son descriptos nuevos restos de un Mylodontinae asignables a cf. Simomylodon Saint-André, Pujos, Cartelle, De Iuliis, Gaudin, McDonald & Mamani Quispe, los cuales provienen del Huayqueriense temprano de la localidad de Arenas Blancas (curso inferior del arroyo Chasicó, provincia de Buenos Aires) y constituyen el primer registro cierto de un Mylodontidae Mylodontinae para el Huayqueriense en esta provincia. Simomylodon ha sido registrado en el Neógeno de Bolivia, por lo que la probable presencia de este género en la provincia de Buenos Aires incrementa notablemente su distribución geográfica.The Mylodontinae (Xenarthra, Mylodontidae) are well represented in the late Miocene (Chasicoan-Huayquerian) and Pliocene (Montehermosan-Chapadmalalan) of South America (with more of a dozen of genera recognized). For the Huayquerian Stage/Age of Argentina the diversity is high (about ten species documented). However, there are not certain records of the subfamily in the Buenos Aires province during the Huayquerian. In this work are described new remains of a Mylodontinae assignable to cf. Simomylodon Saint-André, Pujos, Cartelle, De Iuliis, Gaudin, McDonald & Mamani Quispe, which come from the early Huayquerian of the locality of Arenas Blancas (lower course of Chasicó creek, Buenos Aires province) and constitute the first certain record of a Mylodontidae Mylodontinae for the Huayquerian in this province. Simomylodon was recorded in the Neogene of Bolivia, so the probable presence of this genus in the Buenos Aires province increases notably their geographic distribution.Fil: Oliva, Cristian. Museo Municipal de Ciencias Naturales Carlos Darwin; ArgentinaFil: Brandoni, Diego. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentin

    Sedimentology of the Irene and la toma formations from the neogene of the Claromecó basin, Buenos Aires

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    La cuenca de Claromecó se ubica entre los positivos de Tandil y Ventania. La Formación Irene fue definida para el ámbito del sudoeste de esta Pampa Interserrana, Buenos Aires, para margas claras diaclasadas y lajadas que alcanzan 7 m de espesor en la Estación Irene del Ferrocarril General Roca. Estas rocas que comprenden lo que fue denominado "Araucanense" están subyaciendo limos arenosos carbonáticos rojizos que corresponden a sedimentos pampeanos de la Formación La Toma. De acuerdo a los contenidos fosilíferos y la presencia de escorias, estos sedimentos que coronan las lomas han sido equiparados a las Formaciones Monte Hermoso y Chapadmalal. Se postula entonces una edad pliocena para la porción aflorante (superior) de la Formación Irene y para la formación La Toma. El paisaje es de lomas coronadas por limos entoscados.The Claromecó Basin is located between the horst of Tandil and Ventania. The Irene formation is defined to the west of the Interserrana ("between ranges") Plain, Buenos Aires Province, for light-coloured carbonatic siltstones with joints that sums 7 m thick at the locality close to Irene Railway Station. These rocks comprising the Araucanense are underlying reddish sandy silts assigned to the Pampian sediments of La Toma Formation. According to the fossiliferous and escoria content, these sediments were similar to those outcropping as Monte Hermoso and Chapadmalal formations. It is therefore assumed a Pliocene age for the upper levels of the Irene Formation, as well as to the La Toma Formation. The hilly landscape is crowned by silt with calcretes.Fil: Isla, Federico Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; ArgentinaFil: Dondas, Alejandro. Provincia de Buenos Aires. Municipalidad de General Pueyrredon. Secretaría de Cultura. Museo Municipal de Ciencias Naturales Lorenzo Scaglia; ArgentinaFil: Oliva, Cristian. Museo Municipal de Ciencias Naturales Carlos Darwin. Punta Alta; Argentin

    Macrochorobates scalabrinii (Moreno & Mercerat) (Cingulata, dasypodidae) in the late miocene of the San Juan province (Argentina). Biochronostratigraphical and palaeobiogeographical implications

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    Macrochorobates scalabrinii is reported and described. The remains come from the upper deposits of the Las Flores Formation (Upper Miocene), outcropping at the Iglesia Valley (Iglesia Department, San Juan Province, Argentina). The detailed study of these osteoderms, including the description of some anatomical and morphological characteristics not mentioned before, provides novel information about the carapace and, in turn, probably allows extending the diagnoses of this taxon. The stratigraphic and chronological distribution would support the importance of Macrochorobates scalabrinii as a biostratigraphic indicator for the Huayquerian Stage/Age. On the other hands, this new discovery confirms the previous hypothesis that point out a biogeographic connection between the Pampean and Northwest regions during the Late MioceneApresenta-se aqui osteodermos isolados da carapaça dorsal do dasipodídeo Macrochorobates scalabrinii (Moreno & Mercerat) Os osteodermos provêm dos depósitos superiores da Formação Las Flores (Mioceno Superior), que afl oram no Vale de Iglesia (Departamento de Iglesia, Província de San Juan, Argentina). O estudo morfológico detalhado desses osteodermos, incluindo a descrição de algumas características anatômicas e morfológicas inéditas, proveram novas informações sobre a carapaça que potencialmente podem ser importantes para a diagnose deste táxon. A distribuição estratigráfi ca e cronológica corrobora a importância de M. scalabrinii como indicador bioestratigráfi co para o Piso/Idade Huayqueriense. Por outro lado, este novo registro confi rma a hipótese prévia, que indica uma conexão biogeográfi ca entre as regiões Pampeana e Noroeste, durante o Mioceno tardio.Fil: Contreras, Victor. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Fisicas y Naturales. Instituto de Geologia "Dr. Emiliano Aparicio"; ArgentinaFil: Tomassini, Rodrigo Leandro. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca; ArgentinaFil: Pérez, Miguel. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Fisicas y Naturales. Instituto de Geologia "dr. Emiliano Aparicio"; ArgentinaFil: Oliva, Cristian. Museo Municipal de Ciencias Naturales “Carlos Darwin”; Argentin

    Osteotomies for avascular necrosis of the femoral head.

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    Background: In osteonecrosis of the femoral head (ONFH), blood supply is insufficient for the metabolic requirements of the bone. The initial management is conservative, and, in case of failure, surgery is indicated. Osteotomies aim to change the spatial position of the necrotic portion of the femoral head. This systematic review evaluates the effectiveness and safety of osteotomies for ONFH.Source of data: The systematic review, organized, conducted and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, was performed on PubMed and Google Scholar. We analysed outcomes in term of Harris Hip Score, leg shortening, secondary collapse and blood loss. We also verified the percentage of patients who required total hip replacement (THR) after osteotomy for ONFH.Areas of agreement: A total of 16 articles were selected, including 775 patients and 852 osteotomies [curved varus osteotomy in 369 (43.3%) patients; transtrochanteric rotational osteotomy in 435 (51.05%) patients; half wedge osteotomy in 48 (5.6%) patients]. There was an overall THR conversion rate of 31.5% (268 hips on 852 osteotomies).Areas of controversy: There were no prospective randomized trials, and the outcome measures employed were often heterogeneous.Growing points: Approximately one-third of the osteotomies performed in cases of ONFH are converted to THR over a period of similar to 7 years. In older patients, primary THR should be considered, especially as the conversion to THR after osteotomy is technically demanding.Areas timely for developing research: Randomized clinical studies should be conducted in order to define the parameters of the patient that can direct towards the most suitable osteotomic technique

    Optical Coherence Tomography Angiography in Type 1 Diabetes Mellitus—Report 2: Diabetic Kidney Disease

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    Diabetic nephropathy; Oculomics; Perfusion densityNefropatía diabética; Oculómica; Densidad de perfusiónNefropatia diabètica; Oculòmica; Densitat de perfusióThe purpose of this study is to investigate potential associations between optical coherence tomography angiography (OCTA) parameters and diabetic kidney disease (DKD) categories in type 1 diabetes mellitus (T1DM) patients and controls. A complete ocular and systemic examination, including OCTA imaging tests and bloods, was performed. OCTA parameters included vessel density (VD), perfusion density (PD), foveal avascular zone area (FAZa), perimeter (FAZp) and circularity (FAZc) in the superficial vascular plexus, and DKD categories were defined according to glomerular filtration rate (GFR), albumin-creatinine ratio (ACR) and KDIGO prognosis risk classifications. A total of 425 individuals (1 eye/1 patient) were included. Reduced VD and FAZc were associated with greater categories of GFR (p = 0.002, p = 0.04), ACR (p = 0.003, p = 0.005) and KDIGO risk prognosis classifications (p = 0.002, p = 0.005). FAZc was significantly reduced in greater KDIGO prognosis risk categories (low risk vs. moderate risk, 0.65 ± 0.09 vs. 0.60 ± 0.07, p < 0.05). VD and FAZc presented the best diagnostic performance in ROCs. In conclusion, OCTA parameters, such as VD and FAZc, are able to detect different GFR, ACR, and KDIGO categories in T1DM patients and controls in a non-invasive, objective quantitative way. FAZc is able to discriminate within T1DM patients those with greater DKD categories and greater risk of DKD progression.This research was funded by Fundació La Marató de TV3, La Marató 2015, Diabetis i Obesitat (grant number 201633.10) and Instituto de Salud Carlos III, (through the project PI18/00518, co-funded by European Regional Development Fund “Investing in your future”). This study has undergone peer review separately by both funding bodies. None of the funding bodies have had any access to the study design, the study data or the study conclusions

    Algoritmo de tipo búsqueda tabú para un problema de programación de horarios universitarios vespertinos

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    En este estudio se presenta un modelo de programación no lineal en variables enteras para un problema de programación de horarios universitarios vespertinos y se propone un algoritmo para su solución. El problema consiste en programar asignaturas en un horizonte de planificación considerando profesores, aulas, alumnos, días y un conjunto de restricciones, buscando minimizar la penalidad de no satisfacer los requerimientos de profesores, el número de cambios de sala y el número de periodos libres entre cursos. Se propone un modelo matemático y una implementación de un algoritmo de tipo búsqueda tabú. Para evaluar la efectividad del algoritmo se utilizaron casos de prueba con datos reales del Instituto IPEGE (Chile), en los que el algoritmo es capaz de obtener soluciones factibles en un tiempo razonable. Los parámetros de dicho algoritmo fueron calibrados con los casos de prueba, para posteriormente evaluar su desempeño. Se muestra que este obtuvo mejores soluciones que el método manual
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