2,593 research outputs found
Tsunami excitation by inland/coastal earthquakes: the Green function approach
International audienceIn the framework of the linear theory, the representation theorem is derived for an incompressible liquid layer with a boundary of arbitrary shape and in a homogeneous gravity field. In addition, the asymptotic representation for the Green function, in a layer of constant thickness is obtained. The validity of the approach for the calculation of the tsunami wavefield based on the Green function technique is verified comparing the results with those obtained from the modal theory, for a liquid layer of infinite horizontal dimensions. The Green function approach is preferable for the estimation of the excitation spectra, since in the case of an infinite liquid layer it leads to simple analytical expressions. From this analysis it is easy to describe the peculiarities of tsunami excitation by different sources. The method is extended to the excitation of tsunami in a semiinfinite layer with a sloping boundary. Numerical modelling of the tsunami wavefield, excited by point sources at different distances from the coastline, shows that when the source is located at a distance from the coastline equal or larger than the source depth, the shore presence does not affect the excitation of the tsunami. When the source is moved towards thecoastline, the low frequency content in the excitation spectrum ecreases, while the high frequencies content increases dramatically. The maximum of the excitation spectra from inland sources, located at a distance from the shore like the source depth, becomes less than 10% of that radiated if the same source is located in the open ocean. The effect of the finiteness of the source is also studied and the excitation spectrum is obtained by integration over the fault area. Numerical modelling of the excitation spectra for different source models shows that, for a given seismic moment, the spectral level, as well as the maximum value of the spectra, decreases with increasing fault size. When the sources are located in the vicinity of a shore, the synthetic mareograms calculated at distances greater than the source depth show that the maximum tsunami amplitude decays with decreasing source-to-shore distance. The rate of decay is dependent on the dip, length and depth of the fault. The tsunami intensity, defined as maximum peak-to-peak amplitude, decays with the inland distance of the source from the coast. At an inland distance equal to the source depth, it becomes 4?5 times less than that from a source in the open ocean. If the source is located under the coastline, the intensity of tsunami is approximately the same as for oceanic sources
Métodos para evaluar interacciones entre cuerpos de agua en un humedal y aplicación en dos casos de estudio
La comprensión de la dinámica de ecosistemas dependientes del recurso hídrico subterráneo, como pueden llegar a serlo algunos humedales, parte del conocimiento del sistema hidrológico. Para alcanzar esta meta se aplica una serie de métodos y procedimientos de análisis que comprenden la caracterización hi-drogeológica, la delimitación del área de captura de agua hacia el humedal, el monitoreo piezométrico, la rea-lización de balances de masas. La modelación numérica, los análisis hidrogeoquímicos y los métodos isotópi-cos permiten refinar y validar los modelos conceptuales. En el marco del proyecto Hydrochemical and isotopic techniques for assessment hidrological proccesses on wetlands, promovido entre los años 2006 y 2011 por la Agencia Internacional de Energía Atómica (IAEA), Colombia y Argentina compartieron conoci-miento y experiencias para entender la dinámica de los humedales Ciénaga Colombia y La Salada. En este texto se resumen aspectos metodológicos y los resultados de los dos casos de estudio considerados.The Understanding of ecosystem dynamics, for example the wetlands, depends of the knowledge of the hydrologic system. Many techniques can be used in order to obtain a good conceptual mod-el of the wetlands and its catchment area: hydrogeology, numerical modeling, hydrogeochemestry, and iso-tope hydrology. researchers of Argentina and Colombia studied -According with the project: ―Hydrochemical and isotopic techniques for assessment hidrological proccesses on wetlands‖ (IAEA, 2006 to 2011)- two wet-lands hydrogeology dependent: La salada Pond and Cienaga Colombia Weltand. These projects used method-ologies similar and they obtained validated hydrological models
A computationally fast and accurate procedure for the identification of the Chaboche isotropic-kinematic hardening model parameters based on strain-controlled cycles and asymptotic ratcheting rate
The Chaboche isotropic-kinematic hardening (CIKH) model provides a versatile and realistic description of the material stress–strain behavior under generic multiaxial cyclic loadings. However, identifying the backstress parameters is challenging, and can be formulated as an optimization problem using different approaches. Instead of a computationally expensive pointwise search, in this paper the global properties of the cyclic curves are fitted to the experimental data. The conditions introduced are the hysteresis areas, peak stress values and tangent moduli at the extreme points, however the framework can be easily adapted to other target quantities. One linear and two non-linear backstress components of the kinematic hardening model are introduced, although the analytical equations developed can be used to refine the model further, with more components. Two stabilized cycles are required to identify the main kinematic parameters. New analytical expressions for asymptotic ratcheting rates in uniaxial tests are developed and then used to tune the dynamics of the slightly non-linear (hence, slowest) backstress component. After obtaining the kinematic parameters, isotropic hardening laws can also be identified, by considering the evolution of the extreme points of the strain-controlled cycles before stabilization. Practical demonstrations of the procedure are provided by experimental tests carried out on a 7075-T6 aluminum alloy, 42CrMo4+QT steel, and a high-silicon ferritic ductile cast iron. An accurate reproduction of the material behavior is achieved, at a negligible computational cost
Amino acids as building blocks for carbonic anhydrase inhibitors
Carbonic anhydrases (CAs) are a superfamily of metalloenzymes widespread in all life, classified into seven genetically different families (α–θ). These enzymes catalyse the reversible hydration of carbonic anhydride (CO2), generating bicarbonate (HCO3−) and protons (H+). Fifteen isoforms of human CA (hCA I–XV) have been isolated, their presence being fundamental for the regulation of many physiological processes. In addition, overexpression of some isoforms has been associated with the outbreak or progression of several diseases. For this reason, for a long time CA inhibitors (CAIs) have been used in the control of glaucoma and as diuretics. Furthermore, the search for new potential CAIs for other pharmacological applications is a very active field. Amino acids constitute the smallest fundamental monomers of protein and, due to their useful bivalent chemical properties, are widely used in organic chemistry. Both proteinogenic and non-proteinogenic amino acids have been extensively used to synthesize CAIs. This article provides an overview of the different strategies that have been used to design new CAIs containing amino acids, and how these bivalent molecules influence the properties of the inhibitors
Atypical ulcers: Diagnosis and management
Atypical ulcers show atypical clinical features, histology, localization, and resistance to standard therapies. The persistence of a chronic ulcer despite treatment with standard therapies requires a more specific diagnostic investigation. Diagnosis involves obtaining the history and performing clinical examination and additional tests. A skin biopsy is frequently used to confirm unclear diagnosis. In difficult cases, microbiological and immunohistochem-ical examinations, laboratory blood tests, or instrumental tests should be evaluated. The treatment of atypical wounds is characterized by local systemic therapy and pain control. Our results highlight the need for early diagnosis, and standardized and targeted management by a multidisciplinary wound healing center
Surrounding skin management in venous leg ulcers: A systematic review
Objectives: Chronic venous insufficiency may lead to the development of venous leg ulcers, the most common form of chronic wounds in the lower extremity. Key to venous leg ulcer care is the maintenance of healthy skin surrounding the ulcer, as failure to maintain skin integrity may influence the healing outcome. We thus reviewed the scientific literature looking for assessment and management instruments regarding this common but often neglected issue. Method: The search included all studies published between 2000 and May 2019. Keywords used were: “peri-wound skin care”, “surrounding skin venous ulcers”, “surrounding skin management leg ulcers”, and “peri-lesional skin management”. Results: Management of moisture-balance with the selection of appropriate dressings is the most important target in surrounding-wound skin care. Moreover, contact dermatitis related to products and the dressings themselves is a neglected problem in patients with chronic leg ulcers which clinicians increasingly have to manage. The literature search revealed that there is an increasing interest in the use of noninvasive assessment tools in the field of wound care, and focusing on the surrounding-wound skin plays a role in assessing the potential of wound healing. Transepidermal water loss measurement (TEWL) and ultrasonography are two of the measurement techniques available. Conclusion: The integrity of the surrounding skin is necessary for wound healing, and appropriate management is needed to address this aspect which is part of an overall approach to treating wounds
Energy Demand in Sugarcane Residue Collection and Transportation
Sugarcane production system is in transition, mainly due to its harvesting process. Harvest through burning has been gradually replaced by mechanized processes, providing another by-product to be explored: sugarcane trash. In Brazil, through of the sugarcane trash, São Paulo state itself produces around 210.4 million BOE – barrel of oil equivalent (1,251,952 TJ ), which could supply consumers through cogeneration or for further second generation ethanol. For the sugarcane trash to be collected, mechanized processes are required, such as windrowing, gathering, and transporting. In agricultural production systems, embodied energy is affected by the mechanization level. In order to assess environmental performance by the energy point-of-view, analysis of energy flows provides subsidies for the decision makers. Thus, this study aimed to determine the material and energy flows for sugarcane trash collection and to identify its critical steps. The sugarcane variety grown was RB855113, spaced between rows 1.4 m, in the second cut, and yield of 108 Mg ha-1. The following mechanized operations were evaluated: windrowing, gathering, and transport, using material and energy flow as supporting tools. Regarding the energy balance, sugarcane trash collection system is feasible. Among evaluated operations, gathering is the one that presented higher energy demand. Fuel in harvesting is the main factor that affects energy demand for having sugarcane trash available. Keywords: material flow, mechanized harvest, bioenergy, biofue
Energy Embodiment in Brazilian Agriculture: An Overview of 23 Crops
The amount of energy required to produce a commodity or to supply a service varies from one production system to another and consequently giving rise to differing levels of environmental efficiency. Moreover, since energy prices have been continuously increasing over time, this energy amount may be a factor that has economic worth. Biomass production has a variety of end-products such as food, energy, and fiber; thus, taking into account the similarity in end-product of different crops (e.g.: sunflower, peanuts, or soybean for oil) it is possible to evaluate which crops require less energy per functional unit, such as starch, oil, and protein. This information can be used in decision-making about policies for food safety or bioenergy. In this study, 23 crops were evaluated allowing for a comparison in terms of energy embodied per functional unit. Crops were grouped as follows: starch, oil, horticultural, perennial and fiber, to provide for a deeper analysis of alternatives for the groups, and subsidize further studies comparing conventional and alternative production systems such as organic or genetically modified organisms, in terms of energy. The best energy balance observed was whole sugarcane (juice, bagasse and straw) with a surplus of 268 GJ ha−1 yr−1; palm shows the highest energy return on investment with a ratio of approximately 30:1. For carbohydrates and protein production, cassava and soybean, respectively, emerged as the crops offering the greatest energy savings in the production of these functional foods
Energy Demand in Agricultural Biomass Production in Parana state, Brazil
Energy flow analysis is an interesting approach to assess and to improve sustainability of agricultural production systems, represented by the economy of energy resources and other inputs translated into energy terms. This type of analysis can complement the economic view contributing to more efficient production systems. Moreover, assessing crops with traditional food use may play an important role in energy provision. Energy efficiency tools were applied in order to determine the energy demand as well as the efficiency of the biomass production of several forage crops in mechanized systems conducted at Paraná state, Brazil. Material flow, input and output energy, energy balance, energy return over investment and embodied energy were used and identified that maize and sorghum were the crops that uses energy in the most efficient way, represented by the best results at net energy availability, profitability and embodied energy at the final product. Oat and ryegrass were the crops the presented the least efficient energy uses in the biomass production systems. Keywords: Bioenergy, energy indicators, sustainability, embodied energy.  
Cutaneous Metastasis As The First Manifestation Of Occult Malignant Breast Neoplasia
Cutaneous metastases from primary internal malignancies represent 0.7-9% of patients with cancer. We report a 65year-old female patient referred for evaluation of normochromic papules on the trunk and upper limbs that had been present for three months. A skin biopsy revealed diffuse cutaneous infiltration by small round cell tumors. Immunohistochemistry was positive for AE1/ AE3, CK7, estrogen receptor and mammaglobin. The final diagnosis was cutaneous metastasis of occult breast cancer, since the solid primary tumor was not identified. The location of the primary tumor can not be determined in 5-10% of cases. In these cases, 27% are identified before the patient's death, 57% at autopsy, and the remaining 16% can not be located.915110510
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