139 research outputs found
On -classes of modules with applications
In this paper we introduce some lattices of classes of left R-module relative
to a preradical sigma. These lattices are generalizations of the lattices
R-TORS, R-tors, R-nat, R-conat, of torsion theories, hereditary torsion
theories, natural classes and conatural classes, respectively. We define the
lattices -(R-TORS), -(R-tors), -(R-nat),
-(R-conat), which reduce to the lattices mentioned above, when one
takes sigma as the identity. We characterize the equality between these
lattices by means of the (-HH) condition, which we introduce. We also
present some results about -retractable rings, -Max rings
extending results about Mod-retractable rings and Max rings
Utilización de tarjetas inteligentes para estimar matrices origen-destino. Aplicación al sistema Megabús, Pereira
In the operational planning of transport systems, it is essential to have a characterization of the demand for the service by means of an Origin-estination (OD) Matrix of travels. This matrix is frequently estimated using statistical sampling techniques, which offer high-quality results but require complex design and high cost. It is therefore appropriate to take advantage of the information that is generated from the records of the smart cards used as means of payment in the systems that provide this technology. This source of information allows for obtaining estimates of high-quality Origin–Destination (OD) matrix with a low cost. In this work, it is implemented a methodology for the estimation of an Origin–Destination (OD) matrix between bus stations in the public transport system of MEGABÚS in the city of Pereira. The methodology allows for a debugging in the database taking into account the peculiarities of the system as the forms of income, type of card, and resale of tickets. In addition, it considers the possibility that a user can decide to step down at an intermediate station close to his destination station using the parameterization of a penalty factor that is associated with the walking-travel time in the objective function. The inclusion of the factor does not significantly influence the total percentage of estimated travels. Nevertheless, it recalculates some values of the Origin-Destination (OD) Matrix considering the alight in intermediate stations. The proposed method makes possible to estimate OD matrices for different time windows for any day of the week and different times of the year.En la planificación operativa de los sistemas de transporte es fundamental contar con una caracterización de la demanda del servicio por medio de una matriz origendestino (OD) de viajes. Esta matriz es estimada frecuentemente mediante técnicas de muestreo estadístico que ofrecen resultados de gran calidad pero requieren diseño e implementación compleja y de alto costo. Así, se hace pertinente aprovechar la información de los registros de las tarjetas inteligentes usadas como medios de pago en los sistemas que tienen esta tecnología. Esta fuente de información permite obtener estimaciones de matrices OD de gran calidad con un costo bajo. En este trabajo se implementa una metodología para la estimación de una matriz origen-destino entre estaciones de buses en el sistema de transporte público de Megabús en la ciudad de Pereira. La metodología permite depurar la base de datos teniendo en cuenta las particularidades del sistema, como las formas de ingreso, tipo de tarjeta, reventa de pasajes, y además considera la posibilidad de que un usuario pueda decidir bajarse en una estación intermedia cercana a su estación destino mediante la parametrización de un factor de penalización que está asociado con el tiempo de viaje caminando en la función objetivo. La inclusión del factor no influye significativamente en el porcentaje total de viajes estimados pero sí ajusta algunos valores de la matriz origen-destino, al considerar los descensos en estaciones intermedias. El método posibilita estimar matrices OD para diferentes ventanas de tiempo de cualquier día de la semana y distintas épocas del año
Use of frontal flap for reconstruction of malar region following arteriovenous malformation resection: a case report
Arteriovenous malformations (AVMs) are rare congenital vascular anomalies characterized by abnormal artery-vein connections. These malformations often occur intracranially but can be found in extracranial regions, presenting unique clinical challenges. Diagnosis and staging, typically using the Schobinger clinical classification, are essential, and various imaging techniques aid in the process. Treatment of AVMs is a multidisciplinary effort, with minimally invasive endovascular procedures being preferred, and surgical resection considered for extensive cases. In this case report, a 52-year-old male with an AVM in the malar region underwent successful treatment. The procedure involved preoperative marking, anesthesia, flap division, AVM resection, and flap placement, followed by suturing and a second surgical stage. The successful utilization of a contralateral frontal flap for reconstruction following AVM resection is highlighted. This case underscores the importance of a multi-stage surgical approach and careful flap preservation in AVM treatment, emphasizing the skills of surgeons. Collaboration among various medical specialties is crucial for effectively managing AVMs, combining embolization, resection, and reconstruction for tailored treatment that improves both function and aesthetics
What is the role of ethics in accreditation documentation from a global view?
Ethics in engineering has long been an important element in engineering programmes, however these subjects are often taught at a basic learning level with little attempt to connect to demonstrative learning outcomes. In recent years there has been a step change in the importance of ethics as an integral part of engineering programmes and is reflected in the text of accreditation documents. In this paper we expand our analysis from an earlier study, which focused on four European countries, to understand the role of ethics on a more global scale. We conducted a multi-country analysis on how and where ethics features in accreditation documents in twelve countries across five continents (Belgium, Canada, Colombia, France/Switzerland, Ireland, Japan, Romania, South Africa, Sweden, UK and USA). We identified explicit or implicit references to ethics education, extracted verbs relating to learning outcomes, and compared definitions of key terms. A comparison to Bloom’s taxonomy showed considerably higher frequency of verbs linked to ethics teaching associated to lower levels of cognitive learning. Definitions of terms relating to the process of accreditation were often lacking in documents, highlighting a need for setting terms of reference. This study highlights differences in how ethics is described in accreditation documents. However, more needs to be done to explicitly highlight ethics as an integral part of engineering education. Relying on implicit links to ethics leaves the role of ethics open to interpretation, resulting in uneven emphasis in the translation of ethics within programme designs
Detección del fenómeno de la inversión térmica por medio de la utilización de técnicas de tratamiento digital de imágenes basadas en sistemas de video.
Dentro de los estudios de las zonas costeras se han desarrollado técnicas basadas en sistemas de video, en las cuales el grupo de investigación en Oceanografía e Ingeniería Costera (OCEANICOS) de la Universidad Nacional de Colombia - Sede Medellín, ha venido trabajando durante varios años y ha construido el sistema HORUS. En conjunto con el Centro de Investigaciones del Clima de Colombia, se diseñó la estación de monitoreo Pajarito, ubicada en la ladera occidental del Valle de Aburrá, Medellín, Colombia, con el propósito de utilizar estas técnicas de video en aplicaciones para meteorología. Este trabajo muestra los resultados obtenidos al estudiar el proceso de estabilidad atmosférica en relación con la inversión térmica en el Valle de Aburrá por medio del sistema de monitoreo ambiental basado en cámaras de video. Se encontró mediante este sistema, que en horas de la mañana entre las 06:00 y las 09:30 (UTC-5) hay una transición de estabilidad atmosférica a algunos casos de inversión térmica, fenómeno visible en las imágenes capturadas
Elimination of Bisphenol A and Triclosan Using the Enzymatic System of Autochthonous Colombian Forest Fungi
Bisphenol A (BPA) and triclosan (TCS) are known or suspected potential endocrine disrupting chemicals (EDCs) which may pose a risk to human health and have an environmental impact. Enzyme preparations containing mainly laccases, obtained from Ganoderma stipitatum and Lentinus swartzii, two autochthonous Colombian forest white rot fungi (WRF), previously identified as high enzyme producers, were used to remove BPA and TCS from aqueous solutions. A Box-Behnken factorial design showed that pH, temperature, and duration of treatment were significant model terms for the elimination of BPA and TCS. Our results demonstrated that these EDCs were extensively removed from 5 mg L−1 solutions after a contact time of 6 hours. Ninety-four percent of TCS and 97.8% of BPA were removed with the enzyme solution from G. stipitatum; 83.2% of TCS and 88.2% of BPA were removed with the L. swartzii enzyme solution. After a 6-hour treatment with enzymes from G. stipitatum and L. swartzii, up to 90% of the estrogenic activity of BPA was lost, as shown by the yeast estrogen screen assay. 2,2-Azino-bis- (3-ethylthiazoline-6-sulfonate) (ABTS) was used as a mediator (laccase/mediator system) and significantly improved the laccase catalyzed elimination of BPA and TCS. The elimination of BPA in the absence of a mediator resulted in production of oligomers of molecular weights of 454, 680, and 906 amu as determined by mass spectra analysis. The elimination of TCS in the same conditions produced dimers, trimers, and tetramers of molecular weights of 574, 859, and 1146 amu. Ecotoxicological studies using Daphnia pulex to determine lethal concentration (LC50) showed an important reduction of the toxicity of BPA and TCS solutions after enzymatic treatments. Use of laccases emerges thus as a key alternative in the development of innovative wastewater treatment technologies. Moreover, the exploitation of local biodiversity appears as a potentially promising approach for identifying new efficient strains for biotechnological applications
First-in-human phase I clinical trial of a TLR4-binding DNA aptamer, ApTOLL: Safety and pharmacokinetics in healthy volunteers.
ApTOLL is an aptamer that antagonizes Toll-like receptor 4 and improves functional outcomes in models of ischemic stroke and myocardial infarction. The aim of this study was to characterize the safety and pharmacokinetics of ApTOLL in healthy volunteers. A first-in-human dose-ascending, randomized, placebo-controlled phase I clinical trial to assess safety and pharmacokinetics of ApTOLL (30-min infusion intravenously) was performed in 46 healthy adult male volunteers. The study was divided into two parts: part A included seven single ascending dose levels, and part B had one multiple dose cohort. Safety and pharmacokinetic parameters were evaluated. No serious adverse events or biochemistry alterations were detected at any dose nor at any administration pattern studied. Maximum concentration was detected at the end of the infusion and mean half-life was 9.3 h. Interestingly, exposure increased in the first four levels receiving doses from 0.7 mg to 14 mg (AUC of 2,441.26 h∗ng/mL to 23,371.11 h∗ng/mL) but remained stable thereafter (mean of 23,184.61 h∗ng/mL after 70 mg). Consequently, the multiple dose study did not show any accumulation of ApTOLL. These results show an excellent safety and adequate pharmacokinetic profile that, together with the efficacy demonstrated in nonclinical studies, provide the basis to start clinical trials in patients.This study was sponsored by aptaTargets S.L. (Madrid, Spain) and
was conducted at the Clinical Trials Unit (La Princesa Hospital, Madrid, Spain). The study was supported by a grant from the Spanish
Ministry of Science, Innovation and Universities (RTC-2017-6651-
1). Authors acknowledge David Segarra and M. Eugenia Zarabozo
(aptaTargets S.L.) for their contribution in the management and
funding of the trial, and Alba Singla (Anagram; Barcelona, Spain)
for her contribution in the monitoring of the trial.S
Myliobatis freminvillii, bullnose eagle ray
The Bullnose Eagle Ray (Myliobatis freminvillii) is a medium-sized (to 106 cm disc width) demersal coastal eagle ray that occurs in the Northwest, Western Central, and Southwest Atlantic Oceans from Massachussetts, USA to the Texas coast of the Gulf of Mexico and from Venezuela to Buenos Aires, Argentina and inhabits continental shelves from the surface to a depth of 122 m. Its is captured by artisanal longlines, gillnets, beach seines and also in industrial shrimp trawls. In the Northwest Atlantic, population trend data are available from a deep-water trawl survey in the northern Gulf of Mexico that reveal steep increases in abundance over 2002-2013. There are no known threats in the Northwest and Western Central Atlantic, but in the Southwest Atlantic artisanal fisheries are intense. Further, there are largely unmanaged commercial trawl and longline fisheries in this area. This inshore eagle ray is exposed to intense and often unmanaged fishing pressure throughout the Southwest Atlantic portion of its range, and it has no refuge at depth. Due to the level of exploitation by widespread artisanal fisheries which lack adequate management, it is suspected that this species has undergone a population reduction of >80% over the past three generation lengths (44 years) in the Atlantic South American part of its range, but is stable in the Northwest and Western Central Atlantic. Overall, based on its range, with almost all threats found in the Southwest Atlantic, and the suspected low productivity of the species, the Bullnose Eagle Ray is suspected to have undergone a population reduction of 30-49% in the past three generation lengths (44 years) due to levels of exploitation, and it is assessed as Vulnerable A2bd.Fil: Carlson, J.. National Marine Fisheries Service; Estados UnidosFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Avalos, C.. Fundacion Mundo Azul; GuatemalaFil: Blanco Parra, M. P.. Universidad de Quintana Roo; MéxicoFil: Briones Bell lloch, A.. Direccion de Regulaciones Pesqueras y Ciencias; CubaFil: Cardeñosa, D.. Florida International University; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Derrick, D.. University Fraser Simon; CanadáFil: Espinoza, E.. Direccion Parque Nacional Galapagos; EcuadorFil: Mejía Falla, P. A.. Wildlife Conservation Society; Estados UnidosFil: Morales Saldaña, J. M.. Smithsonian Tropical Research Institute; PanamáFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Naranjo Elizondo, B.. Universidad de Costa Rica; Costa RicaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Perez Jiménez, J. C.. El Colegio de la Frontera del Sur; MéxicoFil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Schneider, E. V. C.. Cape Eleuthera Institute; BahamasFil: Simpson, N. J.. Salvageblue; San Vicente y las GranadinasFil: Talwar, B. S.. Florida International University; Estados UnidosFil: Pollom, R.. University Fraser Simon; Canad
Myliobatis goodei, southern eagle ray
The Southern Eagle Ray (Myliobatis goodei) is a medium-sized (to at least 115 cm DW) coastal eagle ray that occurs in the Western Central and Southwest Atlantic Oceans from South Carolina and Florida, USA and Quintana Roo, Mexico to San Jorge Gulf, Santa Cruz, Argentina. It inhabits continental shelves from inshore to depths of 181 m. It is captured using artisanal longlines, gillnets, beach seines, and in industrial shrimp trawls. This species is inferred to be stable or increasing in the Western Central Atlantic, based on its similarity to the Bullnose Eagle Ray (Myliobatis freminvillei). In the Southwest Atlantic artisanal fisheries are intense, further there are largely unmanaged commercial trawl and longline fisheries in many areas. In Brazil, landings of eagle rays have been reduced by 60% over 2000?2012 in Santa Catarina State, and a reduction of 91% in Rio Grande do Sul since the 1980s. This inshore eagle ray has no refuge at depth and is exposed to intense and often unmanaged fishing pressure throughout the Atlantic South American portion of its range and there it is suspected that this species has undergone a population reduction of >80% over the past three generation lengths (44 years), but is stable in the Western Central Atlantic. Overall, based its range with the almost all threats found in the Southwest Atlantic, the suspected low productivity of the species, this species is suspected to have undergone a population reduction of 30 49% in three generation lengths (44 years) due to levels of exploitation, and it is assessed as Vulnerable A2d.Fil: Carlson, J.. National Marine Fisheries Service; Estados UnidosFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Avalos Castillo, C.. Fundación Mundo Azul; GuatemalaFil: Blanco Parra, M. P.. Universidad de Quintana Roo; MéxicoFil: Briones Bell lloch, A.. Dirección de Regulaciones Pesqueras y Ciencias; CubaFil: Cardeñosa, D.. Florida International University; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Derrick, D.. University Fraser Simon; CanadáFil: Espinoza, E.. Galapagos National Park Directorate; EcuadorFil: Mejía Falla, P. A.. Wildlife Conservation Society; Estados UnidosFil: Morales Saldaña, J. M.. Smithsonian Tropical Research Institute; PanamáFil: Motta, F.. Universidade Federal Do Sao Paulo; BrasilFil: Naranjo Elizondo, B.. Universidad de Costa Rica; Costa RicaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Pérez Jiménez, J. C.. El Colegio de la Frontera del Sur; MéxicoFil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Schneider, E. V. C.. Cape Eleuthera Institute; BahamasFil: Simpson, N. J.. Salvageblue; San Vicente y las GranadinasFil: Talwar, B. S.. Florida International University; Estados UnidosFil: Pollom, R.. University Fraser Simon; Canad
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