1,670 research outputs found
Sustainability of intensive groundwater development: experience in Spain
Intensive aquifer development is common in arid and semiarid countries. The associated economic and social benefits are great, but management is needed and sustainability has to be analysed in the framework of a sound hydrogeological background which includes recharge as a key term. Recharge under natural conditions may greatly differ from the actual value under groundwater exploitation conditions when the aquifer is connected to surface water bodies or evaporation conditions are modified. Actual recharge is not an aquifer property but is variable depending on groundwater abstraction and its pattern, and changes in surface water-groundwater relationships and other circumstances, such as return irrigation flows, leakages, and activities to artificially modify it. Groundwater plays an important role in nature as it sustains spring flow, river base flow, wetlands, and crypto-wetlands, and the related provision of ecological services to mankind. Therefore, developable groundwater resources and their sustainability have to take into account concurrence and the net benefits of capturing it in a given moment and not in other circumstances, and exchanging groundwater-related nature services for the human use of groundwater. The often large storage relative to annual flow of aquifers implies that aquifer development produces effects that may last decades and even affect upcoming human generations. This new dimension, which has economic and sustainability aspects, is not as important for other water resources. Critical flow thresholds have to be considered for groundwater-dependent ecosystems. This is considered from the point of view of water quantity, which is the dominant aspect under arid and semiarid conditions. However, water quality may be as or more important for humans and for nature services, but this needs a separate treatment. The hydrogeological and socio-economic aspects of aquifer behaviour are presented taking into account the experience drawn from some intensively exploited and economically and socially important aquifers, mostly those in La Mancha, in central Spain, but also other intensively exploited Spanish aquifers. Topdown-down administrative decisions to get a given sustainable have resulted in partial failures, but if action is agreed among stakeholders better outcomes could be achieved. Mixed solutions seem the best approach
Design of a new molecularly imprinted polymer selective for hydrochlorothiazide based on theoretical predictions using gibbs free energy
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to select a suitable functional monomer and a porogenic solvent for the synthesis of the MIP. To confirm the results of the theoretical predictions, three MIPs were synthesized and evaluated using the equilibrium batch rebinding method. A water-compatible MIP was prepared using HCTZ as the template and acrylamide as the functional monomer (FM) with ethylene glycol dimethacrylate as the cross-linker and tetrahydrofuran as the porogen. An imprinting factor of 8.24 was obtained. The polymer was characterized by Fourier transform infrared (FTIR), solid-state nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis and nitrogen sorption porosimetry. In addition to HCTZ, six structurally related compounds were tested to evaluate the selectivity of the HCTZ-MIP, and cross-selectivity of the MIP was verified.A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixtur271223002311FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)2007/02306-9141618/2010-8The authors gratefully acknowledge financial support from CNPq (141618/2010-8), FAPESP (2007/02306-9) and FAEPEX-UNICAM
Indirect costs of financial distress
We estimate the indirect costs of financial distress due to lost sales by exploiting real estate (RE) shocks and cross-supplier variation in RE assets and leverage. We show that for the same client buying from different suppliers, the client’s purchases from distressed suppliers decline by an additional 13% following a drop in local RE prices. The effect is more pronounced in more competitive industries, manufacturing, durable goods, less-specific goods, and when the costs of switching suppliers are low. Our results suggest that clients reduce their exposure to suppliers in financial distress
The Textual Similarity of KAM Disclosures for Spanish Companies
We investigate and document the textual similarity of key audit matter (KAM) disclosures
by using KAM items in auditor’s reports of Spanish companies in fiscal years 2017 and 2018. The
main objective is to understand how similar KAMs are disclosed from one year to another. Following
prior literature, we use the cosine similarity to measure the textual similarity between KAM items in
terms of word usage. We classify and analyze KAM items for two consecutive years based on the
following three combinations: (1) KAM topic, (2) KAM topic and auditor, and (3) KAM topic,
auditor, and industry of the client being audited. The results indicate that auditors from the same
accounting firm tend to have a recurring textual similarity under each KAM topic, and such similarity
increases for clients within the same industry. The results add empirical evidence to the understanding
of the recurring textual similarity of KAM disclosure
Variables asociadas al deterioro cognitivo en pacientes de cáncer de colon
Objective: Identify predictors of lower cognitive performance in colon cancer patients treated with surgery before undergoing chemotherapy. Methods: In a sample of 89 colon cancer patients, we evaluated the relation between their cognitive performance in three cognitive domains (executive function, verbal memory and psychomotor skill) and the following variables: Age, sex, years of study, stage, medical prognosis, comorbidity, haemoglobin, anxiety, depression, fatigue, quality of life, physical and psychosocial problems. Results: They are a predominantly male sample (61.8%), over 65 years (mean 66.9) without neuropsychological illness history (89.9%). But, data show correlational relationships between some cognitive performance test and certain variables assessed. There are remarkable negative correlations with age, respiratory problems and social perception of the quality of life, with lower cognitive performance on tests of verbal memory, executive function and psychomotor ability (p <0.05). Also, patients with stage III colon cancer performed worse than those with stage II disease and those with less than five years of study differ from most studies in the three cognitive domains (p < 0.05). Conclusions: The profile of patients with colon cancer at high risk of cognitive deficit is: Old age, with stage III disease, little formal education, breathing problems and a good perception of their quality of social life.Objetivo: Identificar las variables predictoras de menor rendimiento cognitivo en pacientes de cáncer de colon tratados con cirugía que esperan recibir quimioterapia. Método: En una muestra de 89 pacientes de cáncer de colon se valoró la relación entre su rendimiento en tres dominios cognitivos (función ejecutiva, memoria verbal y habilidad psicomotora) y las siguientes variables: edad, sexo, años de escolaridad, estadio, pronóstico médico, comorbilidad, hemoglobina, ansiedad, depresión, astenia, calidad de vida, problemas físicos y psicosociales. Resultados: En la muestra predominan los varones (61,8%), mayores de 65 años (media 66,9), sin antecedentes neuropsicológicos (89,9%). Los datos correlacionales ponen de manifiesto relaciones selectivas entre alguna prueba de rendimiento cognitivo y ciertas variables evaluadas. Se destaca la existencia de correlaciones negativas de la edad, los problemas respiratorios y la percepción social de la calidad de vida con el rendimiento cognitivo en pruebas de memoria verbal, función ejecutiva y habilidad psicomotora (p < 0,05). Así mismo, los pacientes en estadio III del cáncer de colon rinden peor que aquellos con la enfermedad en estadio II y quienes tienen menos de cinco años de estudios difieren de los de más estudios en los tres dominios cognitivos (p < 0,05) Conclusiones: el perfil detectado de los enfermos de cáncer de colon de alto riesgo de déficit cognitivo es: paciente mayor, con enfermedad en estadio III, de escasa formación escolar, que tiene problemas respiratorios y una buena percepción de su calidad de vida social
Non-parametric regression for robot learning on manifolds
Many of the tools available for robot learning were designed for Euclidean
data. However, many applications in robotics involve manifold-valued data. A
common example is orientation; this can be represented as a 3-by-3 rotation
matrix or a quaternion, the spaces of which are non-Euclidean manifolds. In
robot learning, manifold-valued data are often handled by relating the manifold
to a suitable Euclidean space, either by embedding the manifold or by
projecting the data onto one or several tangent spaces. These approaches can
result in poor predictive accuracy, and convoluted algorithms. In this paper,
we propose an "intrinsic" approach to regression that works directly within the
manifold. It involves taking a suitable probability distribution on the
manifold, letting its parameter be a function of a predictor variable, such as
time, then estimating that function non-parametrically via a "local likelihood"
method that incorporates a kernel. We name the method kernelised likelihood
estimation. The approach is conceptually simple, and generally applicable to
different manifolds. We implement it with three different types of
manifold-valued data that commonly appear in robotics applications. The results
of these experiments show better predictive accuracy than projection-based
algorithms.Comment: 17 pages, 15 figure
Ultrarelativistic Bondi--Hoyle Accretion I: Axisymmetry
An ultrarelativistic relativistic study of axisymmetric Bondi--Hoyle
accretion onto a moving Kerr black hole is presented. The equations of general
relativistic hydrodynamics are solved using high resolution shock capturing
methods. In this treatment we consider the ultrarelativistic limit wherein one
may neglect the baryon rest mass density. This approximation is valid in the
regime where the internal energy of the system dominates over the rest mass
energy contribution from the baryons. The parameters of interest in this study
are the adiabatic constant , and the asymptotic speed of the fluid,
. We perform our simulations in three different regimes, subsonic,
marginally supersonic, and supersonic, but the primary focus of this study is
the parameter regime in which the flow is supersonic, that is when . As expected from previous studies the supersonic regimes
reveal interesting dynamics, but even more interesting is the presence of a bow
shock in marginally supersonic systems. A range of parameter values were
investigated to attempt to capture possible deviations from steady state
solutions, none were found. To show the steady state behaviour of each of the
flows studied we calculate the energy accretion rates on the Schwarzschild
radius. Additionally, we also find that the accretion flows are dependent on
the location of the computational boundary, that if the computational boundary
is located too close to the black hole the calculated flow profiles are marred
with numerical artifacts. This is a problem not found in previous relativistic
models for ultrarelativistic hydrodynamic systems.Comment: 16 pages, 15 figures, Typos correcte
Proposta de organização e visualização de grande quantidade de imagens orbitais através de web services.
The organization of satellite imagery seeks to facilitate the presentation and manipulation of spatial information in projects of Land Management's Strategic area from Embrapa Satellite Monitoring, enabling integration between mapped data and interoperability of image data and mapped regions. As a way to standardize this organization, we followed the recommendations of national and international bodies that deal with the standardization of geographic metadata, specifically satellite images. To view this integration, a webmapping interface was created. A webmapping must be prepared to meet the needs of relationship between user and product. In this paper we propose a standardized structure for storage and maintenance of images obtained by satellite sensors aiming its availability on the web through web map services, examples of interoperability. The non-interoperability prevents sharing of information and computing resources. The visualization of web map services takes place through a webmapping that benefits from the organization structure of satellite images proposed in this paper. The hierarchical organization proposed research assistance of satellite images. As they are entered into the database, now new images will be organized in a logical structure, without affecting the search for listings older images. The webmapping allows a direct link between the metadata and geospatial data visualization. Combining web services based on Geographic Information Systems (GIS) in conjunction with the Flex technology allows the creation of Rich Internet Applications (RIA) giving the user more possibilities of interaction via the Web
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