114 research outputs found

    PERSPECTIVA DE GÉNERO Y DESARROLLO EN LA LOCALIDAD DE ZACAMITLA DEL MUNICIPIO DE IXHUATÁN DEL CAFÉ, DEL ESTADO DE VERACRUZ

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    La mujer como actor social en el desarrollo local intenta realizar objetivos personales o colectivos concibiendo al actor social como sujeto pero también como colectividad con intereses, condiciones y características particulares que los identifican como tales, capaces de construir y llevar a cabo en forma conjunta, un proyecto de transformación social para el bienestar de un territorio (Rojas, 2006). El presente artículo aborda la perspectiva de género y desarrollo en la localidad de Zacamitla del municipio de Ixhuatlán del café del estado de Veracruz. La investigación tiene un diseño no experimental, explicativa y de tipo cualitativa. La metodología aplicada combinó la observación de campo y la recolección de información a partir de entrevistas abiertas e historias de vida, con la finalidad de registrar las experiencias conocimientos y relatos de vida de las mujeres de la localidad. Los resultados señalan que la localidad de Zacamitla del municipio de Ixhuatán aún tienen problemas equidad de la mujer en cuanto al empoderamiento económico y político el cual se refleja en la igualdad de oportunidades para acceder a un trabajo remunerado que le permita mejorar sus condiciones de vida y el poder acceder a ocupar un puesto político en su comunidad

    Forecasting return of commercial property in South Africa using macroeconomic factors

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    The forecasting ability of the macroeconomic factors upon South African commercial property return is investigated in this research. Such research is still very novel in South Africa and only Brooks and Tsolacos (2003) has recently investigated this relationship with several European markets. In this research, both direct property returns (IPD) and indirect property returns (J255 and J256) are investigated. The macroeconomic factors that are identified to have some influence on commercial property return are term structure, giltequity ratio, employment index, building plan passed and changing inflation rate (CPIX index). Four different types of models were investigated, namely the univariant ARMA model, the univariant GARCH model, the VAR model and the MLP neural network model. The optimal model for each type is identified using AICc and BIC information criterion techniques. The optimal models are then used in long-term forecasting and short-term forecasting. The ARMA model and the neural network were identified to best predict indirect and direct property returns, respectivel

    Biaxial strength characteristics of selected alloys in a cryogenic environment Final engineering report, 6 Jan. 1965 - 6 May 1966

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    Uniaxial and biaxial strength characteristics and mechanical properties of metallic sheet materials at cryogenic temperature

    Wide-field compensation of monochromatic eye aberrations: expected performance and design trade-offs

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    Contiene: fórmulas y 6 ilustraciones.The optical quality of the human eye varies across the visual field. Hence an exact compensation of the eye aberration for a given field point can give rise to a less-than-optimum compensation in neighboring field regions. We have studied some aspects of this problem and present here an approach to design wide-field (,10°) optically thin correcting elements, e.g., phase plates, deformable mirrors, and liquid-crystal displays. Their expected performance is assessed using actual eye aberration data. Particular attention is given to the design of elements providing a minimum averaged rms residual aberration and those providing a nearly uniform rms residual aberration across a given field.Work supported by the Spanish Ministerio de Ciencia y Tecnología, Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I 1 D 1 I), DPI2002-04370-C02. - This paper was published in Journal of the Optical Society of America A, and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=josaa-20-1-1. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Peer reviewe

    Recursiveness, Switching, and Fluctuations in a Replicating Catalytic Network

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    A protocell model consisting of mutually catalyzing molecules is studied in order to investigate how chemical compositions are transferred recursively through cell divisions under replication errors. Depending on the path rate, the numbers of molecules and species, three phases are found: fast switching state without recursive production, recursive production, and itinerancy between the above two states. The number distributions of the molecules in the recursive states are shown to be log-normal except for those species that form a core hypercycle, and are explained with the help of a heuristic argument.Comment: 4 pages (with 7 figures (6 color)), submitted to PR

    Effects of proton versus photon irradiation on (lymph) angiogenic, inflammatory, proliferative and anti-tumor immune responses in head and neck squamous cell carcinoma

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    International audienceThe proximity of organs at risk makes the treatment of head and neck squamous cell carcinoma (HNSCC) challenging by standard radiotherapy. The higher precision in tumor targeting of proton (P) therapy could promote it as the treatment of choice for HNSCC. Besides the physical advantage in dose deposition, few is known about the biological impact of P versus photons (X) in this setting. To investigate the comparative biological effects of P versus X radiation in HNSCC cells, we assessed the relative biological effectiveness (RBE), viability, proliferation and mRNA levels for genes involved in (lymph)angiogenesis, inflammation, proliferation and anti-tumor immunity. These parameters, particularly VEGF-C protein levels and regulations, were documented in freshly irradiated and/or long-term surviving cells receiving low/high-dose, single (SI)/multiple (MI) irradiations with P/X. The RBE was found to be 1.1 Key (lymph)angiogenesis and inflammation genes were downregulated (except for vegf-c) after P and upregulated after X irradiation in MI surviving cells, demonstrating a more favorable profile after P irradiation. Both irradiation types stimulated vegf-c promoter activity in a NF-κB-dependent transcriptional regulation manner, but at a lesser extent after P, as compared to X irradiation, which correlated with mRNA and protein levels. The cells surviving to MI by P or X generated tumors with higher volume, anarchic architecture and increased density of blood vessels. Increased lymphangiogenesis and a transcriptomic analysis in favor of a more aggressive phenotype were observed in tumors generated with X-irradiated cells. Increased detection of lymphatic vessels in relapsed tumors from patients receiving X radiotherapy was consistent with these findings. This study provides new data about the biological advantage of P, as compared to X irradiation. In addition to its physical advantage in dose deposition, P irradiation may help to improve treatment approaches for HNSCC

    Early Toxicities After High Dose Rate Proton Therapy in Cancer Treatments

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    Background: The conventional dose rate of radiation therapy is 0.01-0.05 Gy per second. According to preclinical studies, an increased dose rate may offer similar anti-tumoral effect while dramatically improving normal tissue protection. This study aims at evaluating the early toxicities for patients irradiated with high dose rate pulsed proton therapy (PT). Materials and methods: A single institution retrospective chart review was performed for patients treated with high dose rate (10 Gy per second) pulsed proton therapy, from September 2016 to April 2020. This included both benign and malignant tumors with ≥3 months follow-up, evaluated for acute (≤2 months) and subacute (>2 months) toxicity after the completion of PT. Results: There were 127 patients identified, with a median follow up of 14.8 months (3-42.9 months). The median age was 55 years (1.6-89). The cohort most commonly consisted of benign disease (55.1%), cranial targets (95.1%), and were treated with surgery prior to PT (56.7%). There was a median total PT dose of 56 Gy (30-74 Gy), dose per fraction of 2 Gy (1-3 Gy), and CTV size of 47.6 ml (5.6-2,106.1 ml). Maximum acute grade ≥2 toxicity were observed in 49 (38.6%) patients, of which 8 (6.3%) experienced grade 3 toxicity. No acute grade 4 or 5 toxicity was observed. Maximum subacute grade 2, 3, and 4 toxicity were discovered in 25 (19.7%), 12 (9.4%), and 1 (0.8%) patient(s), respectively. Conclusion: In this cohort, utilizing high dose rate proton therapy (10 Gy per second) did not result in a major decrease in acute and subacute toxicity. Longer follow-up and comparative studies with conventional dose rate are required to evaluate whether this approach offers a toxicity benefit

    DIFFERENTIAL EFFECTS OF PROTONTHERAPY AND PHOTONTHERAPY ON HEAD AND NECK SQUAMOUS CELL CARCINOMA (HNSCC) POST-TREATMENT AGGRESSIVENESS

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    International audienceHead and neck cancers, the 7 th cause of death worldwide, are currently treated with a combination of surgical resection of the primary tumor, chemotherapy and radiotherapy, depending on the disease stage. Conventional photontherapy nevertheless remains difficult to apply to tumors such as head and neck squamous cell carcinomas (HNSCC), due to the proximity of numerous organs at risk (i.e. salivary glands, esophagus, larynx). Protontherapy has been proposed to treat such sensitive tumors, due to its high precision in tumor targeting. Despite the current therapeutic strategies, the five-year overall survival rate of HNSCC patients is only 53%, with a high percentage of poor response to therapy and a high recurrence rate. Lymph node metastasis, the first sign of tumor progression, has been directly correlated to Vascular Endothelial Growth Factor-C (VEGF-C) expression levels in HNSCC and to VEGF-C-dependent tumoral lymphatic vessel development. In the present study, we investigated the hypothesis that, beside the advantage in dose deposition, protontherapy may show distinct biological properties than photontherapy (at similar doses). We thus examined several in vitro biological behaviors of HNSCC-derived cells when exposed to photons or protons, focusing on molecules with key roles in the progression and prognosis of HNSCC, such as genes/proteins involved in (lymph)angiogenesis/metastasis, inflammation, tumor cell proliferation and anti-tumor immunity, tumorigenic potential. We showed that cell proliferation decreased with the irradiation dose, both in proton and photon irradiated cells. Proton and photon irradiations increased VEGF-C and PD-L1 expression in HNSCC cells. In cells surviving multiple irradiation, key (lymph)angiogenesis and inflammation genes were down-regulated (except for VEGF-C) after protontherapy and up-regulated after photontherapy. Both irradiation types stimulated VEGF-C promoter activity via NF-kB-dependent transcriptional regulation. We conclude that cell resistance, tumor progression and lymphangiogenesis induction is less pronounced after proton irradiation than after photon irradiation. We validated these results by in vivo experiments: Photon-or proton-irradiated HNSCC-derived cells were xenografted subcutaneously into immunodeficient mice. Cells surviving to multiple irradiations by protons or photons generated tumors with higher volume, anarchic architecture and increased density of blood vessels than non-irradiated cells. Increased lymphangiogenesis and a transcriptomic analysis in favor of a more aggressive phenotype were observed in tumors generated with X irradiated cells. Detection of a denser lymphatic vessel network in relapsed tumors from patients receiving conventional X radiotherapy is consistent with these results
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