118 research outputs found

    Detecção de dolinas com apoio de modelos digitais de elevação e imagens de alta resolução : estudo de caso na APA Nascentes do Rio Vermelho - GO

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    Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Geografia, Programa de Pós-graduação, 2019.Os sistemas cársticos escondem seus principais mecanismos de morfogênese na subsuperfície, onde a interação de águas levemente aciduladas com rochas solúveis permite a criação de vazios e a interconexão dos fluxos, acelerando processos erosivos nem sempre visíveis. Uma das expressões superficiais mais marcantes destes mecanismos ligados à espeleogênese são as dolinas, feições consideradas elementares destes ambientes. A presente pesquisa teve como objeto principal as depressões cársticas, a partir das quais revisitou-se conceitos, tipologias genéticas e principais morfologias em trabalhos realizados no Brasil e no mundo. O mapeamento dessas feições é realizado há muito tempo e permite uma série de interpretações de cunho geomorfológico e ambiental. Entretanto, a tarefa de detectar e delimitar dolinas esbarra na resolução das bases de dados disponíveis, dificuldades de estabelecer os limites em campo ou por meio de análises visuais em imagens, grande consumo de tempo e trabalho, além de carregar forte viés de subjetividade. Neste sentido, vários trabalhos mais recentes vêm empregando técnicas modernas e bases de dados de alta resolução para a detecção de dolinas, muitos realizados com certo nível de automação, sobretudo com o uso de Modelos Digitais de Elevação-MDE’s. Baseado nessas experiências e tendo como meta identificar as dolinas da região do alto Rio Corrente e da Área de Proteção Ambiental das Nascentes do Rio Vermelho (APA-NRV), nordeste de Goiás, realizou-se o mapeamento dessas feições em três escalas diferentes. Numa primeira abordagem, identificou-se dolinas prioritariamente por meio de trabalhos de campo em uma pequena área próxima à Gruna da Tarimba, e comparou-se os resultados com a análise visual de MDE’s gerados com dados ALOS-PALSAR e Veículo Aéreo Não Tripulado (VANT). Também foram detectadas de forma semi-automática depressões cársticas para escala abrangente, em toda a bacia do alto Rio Corrente com dados SRTM e ALOS-PALSAR. Por fim realizou-se o mapeamento de uma área significativa com o auxílio do VANT e detectou-se dolinas de forma automatizada em área central da APA-NRV, com vários sistemas de cavernas. Os resultados mostraram a importância da escolha adequada da base de dados, resolução e tamanho da área de abrangência. A partir dos resultados foi possível estabelecer as áreas mais carstificadas, tipologias mais usuais de dolinas e os principais processos atuantes na configuração do relevo local, com importante papel dos materiais e da dupla dinâmica erosiva, superficial e subterrânea.Karst systems hide their main mechanisms of morphogenesis in the subsurface, where the interaction of slightly acidified waters with soluble rocks allows the creation of voids and the interconnection of flows, accelerating erosive processes that are not always visible. One of the most important superficial expressions of these mechanisms linked to speleogenesis are dolines, features considered elementary in these environments. The present research had as its main object karst depressions, from which concepts, genetic typologies and main morphologies were revisited in works carried out in Brazil and in the world. The mapping of these features has been carried out for a long time and allows for a series of interpretations of a geomorphological and environmental nature. However, the job of detecting and delimiting dolines comes up against the resolution of the available databases, difficulties in establishing limits in the field or through visual analysis in images, great consumption of time and work, in addition to carrying a strong bias of subjectivity. In this sense, several more recent works have been using modern techniques and high-resolution databases for the detection of dolines, many carried out with a certain level of automation, especially with the use of Digital Elevation Models-MDE's. Based on these experiences and aiming to identify the dolinas in the upper Rio Corrente region and the Environmental Protection Area of the Rio Vermelho Springs (APA-NRV), northeast of Goiás, the mapping of these features was carried out at three different scales. In a first approach, dolines were identified primarily through fieldwork in a small area close to Tarimba Cave, and the results were compared with the visual analysis of MDE's generated with ALOS-PALSAR data and Unmanned Aerial Vehicle (UAV) . Karst depressions for a comprehensive scale were also semi-automatically detected throughout the upper Corrente river basin with SRTM and ALOS-PALSAR data. Finally, a mapping of a significant area was carried out with the aid of the UAV and dolines were automatically detected in the central area of the APA-NRV, with several cave systems. The results showed the importance of choosing the appropriate database, resolution and size of the coverage area. Based on the results, it was possible to establish the most karstified areas, the most common types of dolines and the main processes acting in the configuration of the local relief, with an important role of the materials and the double erosive, superficial and underground dynamics

    Polavtomatski pristop za kartiranje vrtač na brazilskem pokritem krasu: pot do ocene ranljivosti

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    Doline mapping is paramount in the vulnerability and risk assessment of the underground karst environment by identifying cave-ground connectivity points at the surface. However, manual mapping is labour-intensive, slow and subjective, especially on a large scale. Therefore, the present study adopted a GIS-based semi-automatic approach for mapping large and medium-sized depressions/dolines in the Corrente river basin in Brazil, with a particular focus on the environmentally preserved areas of river Vermelho (APANRV Portuguese abbreviation) using remote sensing (DEM and Google Earth imagery) and field-based observations. Seven typical dolines forms (e.g., cockpit with drain insertion, collapse, collapse with river capture, suffosion, solution, cover collapse, and buried) are found from extensive field surveys. As an outcome of the proposed approach, two hundred and thirty-two medium to large-sized dolines have been identified and categorised into three main groups based on the cave density and local geology G1, G2, and G3. The high density of identified dolines (164 known caves) in G1 provides reconnaissance for future speleological works in the preserved areas. Additionally, the presence of a considerable number of dolines in the adjoining areas (G2 and G3) stresses the need to revise the existing boundaries of the APANRV. Results correlate well with the dolines sites marked using field surveys and Google Earth images. This doline mapping may help researchers in the groundwater vulnerability assessment and the protection of speleological heritage preserved in the caves.Kartiranje vrtač je nadvse pomembno za oceno ranljivosti in tveganja podzemnega kraškega okolja, saj določa točke povezanosti med jamami in tlemi na površju. Vendar je ročno kartiranje zelo zahtevno, časovno zamudno in subjektivno, zlasti v velikih merilih. Zato je bil v tej študiji uporabljen polavtomatski pristop z uporabo orodij GIS za kartiranje velikih in srednje velikih kraških globeli/vrtač v porečju reke Corrente v Braziliji s posebnim poudarkom na okoljsko ohranjenih območjih reke Vermelho (portugalsko APANRV) z uporabo daljinskega zaznavanja (posnetki DEM in programa Google Earth) in na podlagi terenskih opazovanj. Na podlagi obsežnih terenskih raziskav je ugotovljenih sedem značilnih oblik vrtač (npr. kokpit z drenažo, udornica, udornica z zajezitvijo reke, sufozija, škavnica, udornica, nastala z udorom/rušenjem jamskega stropa, in udornice, nastale z zasutjem). Kot rezultat predlaganega pristopa je bilo opredeljenih 232 srednje velikih do velikih vrtač, ki so bile glede na gostoto vrtač in lokalno geologijo razvrščene v tri glavne skupine G1, G2 in G3. Velika gostota opredeljenih vrtač (164 znanih jam) v skupini G1 zagotavlja predhodni pregled za prihodnja speleološka dela na ohranjenih območjih. Poleg tega prisotnost velikega števila vrtač na sosednjih območjih (G2 in G3) poudarja potrebo po ponovnem pregledu zdajšnjih meja APANRV. Rezultati se dobro ujemajo z lokacijami vrtač, kartiranimi na podlagi terenskih raziskav in posnetkov programa Google Earth. To kartiranje vrtač lahko raziskovalcem pomaga pri oceni ranljivosti podzemne vode in pri zaščiti speleološke dediščine, ohranjene v jamah

    A semi-automatic approach for doline mapping in Brazilian covered karst: the way forward to vulnerability assessment

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    peer reviewedDoline mapping is paramount in the vulnerability and risk assessment of the underground karst environment by identifying cave-ground connectivity points at the surface. However, manual mapping is labour-intensive, slow and subjective, especially on a large scale. Therefore, the present study adopted a GIS-based semi-automatic approach for mapping large and medium-sized depressions/dolines in the Corrente river basin in Brazil, with a particular focus on the environmentally preserved areas of river Vermelho (APANRV Portuguese abbreviation) using remote sensing (DEM and Google Earth imagery) and field-based observations. Seven typical dolines forms (e.g., cockpit with drain insertion, collapse, collapse with river capture, suffosion, solution, cover collapse, and buried) are found from extensive field surveys. As an outcome of the proposed approach, two hundred and thirty-two medium to large-sized dolines have been identified and categorised into three main groups based on the cave density and local geology G1, G2, and G3. The high density of identified dolines (164 known caves) in G1 provides reconnaissance for future speleological works in the preserved areas. Additionally, the presence of a considerable number of dolines in the adjoining areas (G2 and G3) stresses the need to revise the existing boundaries of the APANRV. Results correlate well with the dolines sites marked using field surveys and Google Earth images. This doline mapping may help researchers in the groundwater vulnerability assessment and the protection of speleological heritage preserved in the caves

    CARACTERIZAÇÃO ESPELEOLÓGICA DA ESTAÇÃO ECOLÓGICA MICO-LEÃO-PRETO / SP

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    O presente trabalho, realizado pelo Centro Nacional de Pesquisa e Conservação de Cavernas – CECAV, objetiva avaliar o potencial espeleológico, caracterizando as cavidades dentro do seu ambiente cárstico, da Estação Ecológica (ESEC) Mico Leão Preto / SP. O CECAV em conjunto com as Unidades de Conservação vem contribuindo com a gestão de áreas protegidas, que possuem cavidades naturais subterrâneas no seu interior ou no seu entorno. A presença de cavidades no interior de unidades de conservação funciona como um atrativo adicional, tanto para atividades turísticas e científicas como educativas. As duas cavidades descritas na região do Pontal do Paranapanema perfazem provavelmente as únicas ocorrências para um raio de muitos quilômetros. Esse vazio em ocorrências espeleológicas denota uma importância relativa a estes abrigos o que requer forma de manejo adequado, exigindo um maior controle fiscalizatório na área

    UAV-based doline mapping in Brazilian karst. A cave heritage protection reconnaissance

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    Abstract Dolines are depressions in the soluble ground that indicates the degree of karstification. They may also act as connection points (vulnerability spots) between the surface and underground for the transmission of runoff, sediments, and pollutants. The delineation of these spots (dolines) is a crucial step in environmental management through land use planning to protect the karst underground, which is rich in flora and fauna. This requirement can benefit from a cost-effective, accessible, and non-invasion high-resolution investigation generating digital elevation models (DEMs) from unmanned aerial vehicle (UAV) imagery and automated object detection techniques. This study examines the capabilities of UAV-based DEM in detecting dolines across 50 km2 in the environmentally protected area of river Vermelho (APANRV – Área de Proteção Ambiental das Nascentes do Rio Vermelho). Initially, an automatic objects (doline and no-doline) detection algorithm was applied to the DEM, followed by a visual inspection to differentiate doline from possible dolines in orthomosaic photos, topographic profiles, and shaded UAV-based relief (digital terrain model; DTM and DSM). For the redundancy checking, a cluster analysis with four tests was conducted. The objects generated from the best clusters and morphological analysis were gathered in the same base for visual inspection. Out of a total of 933 objects identified, 41% were obtained from the DSM base, 25% from the perimeter-to-area ratio, and 34% through convergence between the two-analyses. Subsequently, the resulting doline typologies are discussed in reference to their proximity to hydrogeological features and their impacts on underground vulnerability. The findings aligned with the previous research as dolines were highly concentrated near sites where carbonates come in contact with siliciclastic sediments

    Functionalized asphalt mixtures: Photocatalytic, superhydrophobic and self-cleaning properties

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    Functionalization of road pavement asphalt mixtures provides new capabilities that can mitigate problems like air pollution and road accidents. In this research, nano-TiO2 and micro-ZnO were deposited through an aqueous solution by spraying it over the surface of asphalt mixture samples in order to promote the photocatalytic, superhydrophobic and self-cleaning capabilities. Tested by degradation of Rhodamine B, to assess the Photocatalytic Efficiency, and by Water Contact Angle (WCA), to assess the wettability of the materials, this technique can be used to promote these multifunctional capabilities in asphalt mixtures. With these enhanced surface characteristics, road safety and the environment, through pollutants degradation like NOx and SO2, will be improved.This work was supported by FCT—Fundação para a Ciência e Tecnologia—through the project PEst-OE/ECI/UI4047/2014info:eu-repo/semantics/publishedVersio

    Does Quantitative Left Ventricular Regional Wall Motion Change after Fibrous Tissue Resection in Endomyocardial Fibrosis?

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    OBJECTIVES: We compared left ventricular regional wall motion, the global left ventricular ejection fraction, and the New York Heart Association functional class pre- and postoperatively. INTRODUCTION: Endomyocardial fibrosis is characterized by fibrous tissue deposition in the endomyocardium of the apex and/or inflow tract of one or both ventricles. Although left ventricular global systolic function is preserved, patients exhibit wall motion abnormalities in the apical and inferoapical regions. Fibrous tissue resection in New York Heart Association FC III and IV endomyocardial fibrosis patients has been shown to decrease morbidity and mortality. METHODS: We prospectively studied 30 patients (20 female, 30&plusmn;10 years) before and 5&plusmn;8 months after surgery. The left ventricular ejection fraction was determined using the area-length method. Regional left ventricular motion was measured by the centerline method. Five left ventricular segments were analyzed pre- and postoperatively. Abnormality was expressed in units of standard deviation from the mean motion in a normal reference population. RESULTS: Left ventricular wall motion in the five regions did not differ between pre- and postoperative measurements. Additionally, the left ventricular ejection fraction did not change after surgery (0.45&plusmn;0.13% x 0.43&plusmn;0.12% pre- and postoperatively, respectively). The New York Heart Association functional class improved to class I in 40% and class II in 43% of patients postoperatively (p<0.05). CONCLUSIONS: Although endomyocardial fibrosis patients have improved clinical symptoms after surgery, the global left ventricular ejection fraction and regional wall motion in these patients do not change. This finding suggests that other explanations, such as improvements in diastolic function, may be operational

    Canine Transmissible Venereal Tumor in the Larynx with Pulmonary Metastasis

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    Background: Canine transmissible venereal tumor (TVT) is one of the most common canine neoplasms in Brazil. Lesions develop mainly in the genital tissue and less frequently in other areas, in the extragenital form. Metastasis is rare, and the disease progression depends on the patient's immune status. The treatment of choice is chemotherapy with vincristine sulfate, considered an effective and safe modality. The present work describes the first case of extragenital TVT in the larynx with pulmonary metastasis at the time of diagnosis. Case: An approximately 4-month-old mixed-breed bitch was attended manifesting acute clinical respiratory signs. The patient had been rescued from the street 2 months beforehand. Physical examination revealed pale mucous membranes and crackling pulmonary auscultation. Thoracic radiography was performed in 3 projections, showing multiple nodules in the lung parenchyma, followed by cytopathological examination using fine needle puncture guided by thoracic ultrasound, confirming the diagnosis of TVT. Considering the cytological finding and the absence of primary tumor lesions in the genital, oral, cutaneous or nasal regions, endoscopy was performed in order to locate a possible primary focus. The exam revealed a small erythematous tumor with smooth and regular surface, measuring approximately 2.5 cm, located in the larynx, between the arytenoid cartilages. Chemotherapy was performed with vincristine sulfate with radiographic follow-up throughout the treatment. Full remission of the pulmonary and laryngeal nodules was achieved at the end of the protocol. The animal remained in complete remission for a period of 2 years. Discussion: TVT is more frequently observed in animals of active reproductive age, and rarely in animals under 1 year of age, as in the case described here. When considering extragenital lesions, the manifestation can be single or multiple, occurring more frequently in the cutaneous, oral and nasal forms. This case describes a laryngeal lesion with pulmonary involvement, without lesion in the genitalia or any other site. Cases of TVT in young and prepubescent animals, associated with extragenital involvement and aggressive behavior, similar to this case, have been described in literature, but never in this location. Literature suggests there is a relationship with the immune status of such patients, which do not have a well-developed immune system, facilitating disease progression. In these animals, transmission can be maternal, since in some cases the patient develops the disease without having contact with other animals except the mother. This form of transmission would facilitate the extragenital form in the oral cavity, airways and ocular region, related to licking, lactation and direct contact. Vincristine sulfate chemotherapy, considered the treatment of choice, was effectively used in this case, despite the atypical form. The TVT prognosis tends to be favorable, with the exception of the aggressive presentations with the presence of distant metastases. However, in the case described here, even though metastatic pulmonary nodules were present, complete remission was achieved, with survival exceeding 2 years. The development of TVT in the larynx is a rare form of the disease, and this report is possibly the first description of this tumor location. Thus, we highlight the importance of a complete investigation of the patient and of TVT as a differential diagnosis in this location. Keywords: dog, bitch, coitus, neoplasm, round cells, extragenital. Título: Tumor venéreo transmissível canino em laringe com metástase pulmonar Descritores: cão, cadela, coito, neoplasia, células redondas, extragenital

    Remoção de matéria orgânica natural em águas usando cavitação hidrodinâmica e peróxido de hidrogênio (CH-H2O2)

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    The presence of natural organic matter (NOM) in water does not present direct risk to the human body or to the environment. However, its presence along with other pollutants can lead to countless issues and damage human health and the environment. The hydrodynamic cavitation (HC) phenomenon started being used in the early 21st century as a process capable of treating supply-water and wastewater based on pollutant and pathogen degradation. Process effectiveness increases when it is combined to chemical agents, creating an advanced oxidation process (AOP). Although several studies have presented broaden applications for the HC process, its use for NOM removal from supply-water was not yet assessed; therefore, it remains a gap in scientific knowledge. The aim of the current study is to assess HC potential in NOM removal. In order to do so, the experiments were carried out in bench scale hydrodynamic cavitation system operated at batch model within 15-min duration period-of-time. In addition, decantation experiments (24-h period-of-time) were performed in order to check HC influence on molecules found in reaction medium after the exposure of NOM to the phenomenon. NOM was produced by a synthetic humic acid (HA) matrix at fixed concentration of 100 ppm. In total, 16 experiments were carried out; each experiment was featured by the following pair: pH (2.6, 3.0, 3.5 and 5.5) and hydrogen peroxide (0, 1, 5 and 30 mL). The best removal efficiencies (34%-36%) were observed in the most acidic pH ranges (2.6-3.0) at H2O2 concentration of 15mL. Results have presented high NOM removal efficiency (approximately 90%) after decantation at the most acidic pH ranges, as well. It can be explained by the fact that hydrodynamic cavitation in acid solution can break molecular structures suspended in the liquid medium, which favors decantation. Based on the present study, hydrodynamic cavitation with hydrogen peroxide addition can remove NOM from water; moreover, pH control is an essential factor for process development
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