Angel Pizo Garcia - Academia.edu (original) (raw)

Papers by Angel Pizo Garcia

This paper seeks to contribute by presenting an assessment of the relevant literature on banking ... more This paper seeks to contribute by presenting an assessment of the relevant literature on banking and the endogenous money supply. The focus is placed on the Post Keynesian perspective, though traditional approaches are briefly discussed as well. The paper argues that, due to scope economies, banks are mistakenly confused with financial intermediaries; a common finding in the traditional literature. This is not the case of both the Post Keynesian view and the Circuit approach. Those perspectives, on the contrary, by reversing the causal link implied by the quantity theory of money, the base-multiplier and the saving-investment cycle as well as by focusing on a flow-perspective of money and on the asset side of banks’ balance sheets, are both able to explain the core of the banking business and, hence, the very nature of the endogenous money supply. The paper shares the view of Screpanti (1997) for whom "...Banks make the generic credit risk saleable". They transform r...

REVISTA CIÊNCIA AGRONÔMICA, 2020

Agricultural ground vehicles often have to traverse unstructured terrain, i.e., terrain whose con... more Agricultural ground vehicles often have to traverse unstructured terrain, i.e., terrain whose conditions cannot be precisely predicted during its displacement. Such characteristics restrict the use of robots in the agricultural field because their stability could be compromised by their interaction with the terrain. As it does not have a human operator capable of observing, predicting, and controlling the interaction of the vehicle with the terrain. Therefore, a robot must deal with the unpredictability caused by this interaction, a task that was previously performed by the human operator. Given the relevance of the topic, this study investigates the literature on agricultural unmanned ground vehicles from the stability point of view, and also presents relevant criteria for dealing with the stability of agricultural robots in terms of their design and selection.

This paper provides a simple microeconomic evaluation of the determinants of credit card holding ... more This paper provides a simple microeconomic evaluation of the determinants of credit card holding in Italy. Using a Probit model, the analysis mostly concentrates on the demand side of the credit card market. Thus, the focus has been on identifying specific individual characteristics of Italian households, which show to be statistically significant for determining the probability of possessing a credit card. The data has been entirely collected from the Survey of Italian households’ Income and Wealth 2002. Relevant expected results are derived from this study. In the first place, the probability of holding a credit card is shown to move up with increases in average family income perceptions, although further increases to higher levels of income show weak diminishing returns captured by a negative quadratic association included in the estimation. Secondly, the age of the head of household is also shown to be a positive determinant even though decreasing returns are as well significant...

Revista Brasileira de Engenharia Agrícola e Ambiental, 2018

In the mechanical harvesting of sugarcane, a self-propelled harvester is used in conjunction with... more In the mechanical harvesting of sugarcane, a self-propelled harvester is used in conjunction with an agricultural implement named infield wagon, which has the function of storing and transporting the harvested product. Much of the cost of sugarcane production comes from this operation (30 to 60%). Among the operational costs of agricultural machinery, the cost of repair and maintenance (CRM) is relevant. Therefore, the objective of this study was to determine the parameters of the CRM mathematical model based on the life (hours of use) for the infield wagon, using the method of the American Society of Agricultural and Biological Engineers (ASABE). These CRM models were obtained for two sets of infield wagon from different manufacturers and their costs over up to 12 years. The model was adjusted and then validated using descriptive statistics methods. Fitted CRM equations were different for each analyzed set of infield wagon and, therefore, are a valuable tool in the management of me...

REVISTA CIÊNCIA AGRONÔMICA, 2019

Family farming seeks to use less-aggressive agricultural practices, however, there is little mach... more Family farming seeks to use less-aggressive agricultural practices, however, there is little machinery available that is suitable for the reality of this sector. This has led to the use of technically incorrect practices, which have contributed to the impoverishment, compaction and desertification of agricultural soils. Punch seeders are seen as a promising alternative for carrying out sowing in family farming, as they employ localised seed distribution with less disturbance of the soil and the consequent preservation and conservation of its structure. The aim of this study was to evaluate the quality of seed distribution by a punch seeder used in family farming. The experiment was carried out in a soil classified as a Red-Yellow Argisol. Descriptive statistics were used to evaluate the quality of seed distribution by the punch system. Statistical Process Control was adopted to evaluate quality control in the seed distribution process. The results showed that the performance of the punch seeder was similar to that of the precision pneumatic seeder, with 90.2% acceptable spacing. As demonstrated by the SPC study that showed the process to be compatible with quality standards, the punch seeder is therefore a viable alternative in the sowing process for family farming, since an improvement in sowing quality, with a precision of 88.4% was obtained. The punch system resulted in less soil disturbance when compared to the disc harrow and manual seeder, and proved to be an effective solution for conservation agriculture.

Water, 2018

The supply of raw water to the inhabitants of metropolises is not a trivial problem, and involves... more The supply of raw water to the inhabitants of metropolises is not a trivial problem, and involves many challenges, both in terms of the quantity and quality of this water. When these metropolises are located in semiarid regions, this challenge takes on enormous proportions, and in many situations, there are no sustainable solutions, especially in times of global climate change. One hypothesis to try to mitigate this problem in coastal cities is the underwater adduction of rivers. The objective of this paper was to make the abstraction of drinking water in the mouths of great rivers near semi-arid regions. This water would be led by a pipeline below the water level and would follow the route of the seacoast, where the energy to move the water would be supplied by an axial hydraulic pump embedded in the pipeline by water-cooled electric motors driven by the energy generated from offshore wind turbines. Estimates have been made for the four metropolises in semi-arid regions: Fortaleza-Brazil, Dalian-China, Tel Aviv-Israel, and Gaza-Palestine, where it was possible to calculate economic viability through the Present Worth Value, the internal rate of return, and payback. The results indicated that Fortaleza had economic viability under restrictions. Dalian proved the ideal result. Tel Aviv and Gaza both had great economic viability, but only if Egypt agreed to supply water from the Nile. This paper proved that the management of the water supply for human consumption through the underwater adduction of rivers could be achieved with real clearance for any deficits in the volume of water that due to global climate change are becoming more frequent.

Revista Bcv, 2007

Beyond the Theory of Optimal Monetary Zones, this work presents an analysis about the costs and b... more Beyond the Theory of Optimal Monetary Zones, this work presents an analysis about the costs and benefits of regional integration. In relation to the case of the European Union, we study the consequences and justifications behind the nominal convergence criteria in the matter of inflation rates, interest types, exchange rates, fiscal deficit and public indebtedness, basic variables in the monetary and financial integration process. In the light of the European experience, the work also deals with the Latin American integration processes based on the point of view of its financial flows, in order to draw lessons that would feed the policy makers with recommendations, taking into account the implications to the inside (in the growth and development processes), and to the outside (in the relationship with third parties). It is deduced that integration in the financial field could be realized through formal efforts made towards that end, but it could also emerge with no preexisting agreements, as the result of the interest of international actors in a particular market. Informal integration has been the most common case in the Latin American region; and even though it has allowed for certain good use of this area by the region, the path leading to this goal is still long.

Revista Venezolana De Analisis De Coyuntura, 2006

This paper provides a review of the philosophical traditions on the study of social inequality an... more This paper provides a review of the philosophical traditions on the study of social inequality and recent theories of justice. On the one hand, it sets forth the fundamental ideas of those philosophers who have been labeled as conservative or functionalists and have defended inequality as something which is expected to be just and inevitable. On the other hand, it presents, as well, the ideas of those philosophers known as radicals who state not only that social inequality is unjust, but rather that it is evitable as well. Subsequently, the paper describes the main ideas concentrated in what Lenski (1993) calls the growing dialectic synthesis of the theory of social stratification which incorporates elements from both traditions. The paper reviews the theories of distribution based on the principles of political economy proposed by the classical economists, and contrasts them with those proposed by the marginalist theory and the theory of social stratification. In doing so, the paper briefly considers the relationship between technology, and political instruments of distribution such as needs, power and privileges. Regarding the recent theories of justice, the paper mainly focuses on the proposals of Rawls (1971) and Nozick (1974). Finally, with respect to the current state of affairs, the roles of information-based technology and modern post-Bretton Woods financial institutions are briefly discussed-in terms of their complementarities-to explain the well known persistent increase in global social inequality.

Se pretende que todos los miembros de la comunidad educativa, aprovechando las nuevas tecnologías... more Se pretende que todos los miembros de la comunidad educativa, aprovechando las nuevas tecnologías, dispongan de un foro de discusión, un medio de información y de participación en la vida del centro. Los objetivos son introducir a la comunidad educativa en el uso de Internet y ofrecer una intranet; difundir las actividades del centro por internet; y facilitar al entorno social el acceso a los recursos públicos del instituto. Los profesores crean un equipo de trabajo, un enlace con los departamentos, que abarca todos los niveles y centros de interés, y elaboran y actualizan el sitio web. Los estudiantes se distribuyen en pequeños grupos de niveles diferentes que colaboran en horario lectivo o no, y elaboran trabajos de investigación. En la primera fase se difunde la actividad y objetivos, se motiva la participación y se elabora el sitio web. Después se incorporan todos los departamentos didácticos y crean páginas interactivas. Los materiales elaborados son información general de trám...

IEEE PES Power Systems Conference and Exposition, 2004.

This paper shows the capacity of modern computational techniques such as the self-organizing map ... more This paper shows the capacity of modern computational techniques such as the self-organizing map (SOM) as a methodology to achieve the classification of the electrical customers in a commercial or geographical area. This approach allows to extract the pattern of customer behavior from historic load demand series. Several ways of data analysis from load curves can be used to get different input data to "feed" the neural network. In this work, we propose two methods to improve customer clustering: the use of frequency-based indices and the use of the hourly load curve. Results of a case study developed on a set of different spanish customers and a comparison between the two approachs proposed here are presented.

Revista Brasileira de Engenharia Agrícola e Ambiental, 2010

A produção em ambientes protegidos é uma técnica por meio da qual se objetiva proteger flores e h... more A produção em ambientes protegidos é uma técnica por meio da qual se objetiva proteger flores e hortaliças contra a ação dos elementos meteorológicos que a afetam, além de permitir ambientes favoráveis de produção durante todo o ano, com vantagens produtivas e comerciais. Um fator importante da produção em estufas é o controle da temperaturae da umidade relativa do ar. A automação do controle do ambiente possibilita o aumento da qualidade dos produtos, maior eficiência e uso racional dos recursos. O objetivo do presente trabalho foi desenvolver um sistema de controle de temperatura e umidade relativa do ar para o protótipo de uma ambiente protegido em escala reduzida, utilizando-se dos conceitos da lógica Fuzzy. As variáveis de entrada foram a temperatura e a umidade do ar e as variáveis de saída foram as atuações nos sistemas de aquecimento e de umidificação do ambiente. O processo de controle do ambiente foi simulado e os parâmetros do projeto foram ajustados. Os resultados obtidos na simulação demonstraram que os ajustes das variáveis Tar e UR, baseados no sistema de inferência Fuzzy desenvolvido, foram satisfatórios para o desempenho do sistema de controle do ambiente protegido.

Engenharia Agrícola, 2012

The objective of this study was to model mathematically and to simulate the dynamic behavior of a... more The objective of this study was to model mathematically and to simulate the dynamic behavior of an auger-type fertilizer applicator (AFA) in order to use the variable-rate application (VRA) and reduce the coefficient of variation (CV) of the application, proposing an angular speed controller θ' for the motor drive shaft. The input model was θ' and the response was the fertilizer mass flow, due to the construction, density of fertilizer, fill factor and the end position of the auger. The model was used to simulate a control system in open loop, with an electric drive for AFA using an armature voltage (V A) controller. By introducing a sinusoidal excitation signal in V A with amplitude and delay phase optimized and varying θ' during an operation cycle, it is obtained a reduction of 29.8% in the CV (constant V A) to 11.4%. The development of the mathematical model was a first step towards the introduction of electric drive systems and closed loop control for the implementat...

IEEE Latin America Transactions, 2011

One of the most important tasks of a software development project manager is to produce accurate ... more One of the most important tasks of a software development project manager is to produce accurate time and effort estimations. Improving the estimation accuracy is a widely recognized benefit for several software development processes. In order to achieve these objectives, there are proposals based on Artificial Intelligence techniques and specifically artificial neural networks. This paper proposes an optimization methodology for searching the best neural model applicable to the effort estimation of software projects. This will draw on a set of known factors in the early stages of development, outside the complex calculation of function points, which would entail a high level of maturity and definition of the project. This methodology has allowed, on the one hand, ensure the adequacy of the proposed neural network model and, on the other hand, optimize the performance, both in time and accuracy.

Engenharia Agrícola, 2014

The present study shows the development, simulation and actual implementation of a closed-loop co... more The present study shows the development, simulation and actual implementation of a closed-loop controller based on fuzzy logic that is able to regulate and standardize the mass flow of a helical fertilizer applicator. The control algorithm was developed using MATLAB's Fuzzy Logic Toolbox. Both open and closed-loop simulations of the controller were performed in MATLAB's Simulink environment. The instantaneous deviation of the mass flow from the set point (SP), its derivative, the equipment´s translation velocity and acceleration were all used as input signals for the controller, whereas the voltage of the applicator's DC electric motor (DCEM) was driven by the controller as output signal. Calibration and validation of the rules and membership functions of the fuzzy logic were accomplished in the computer simulation phase, taking into account the system's response to SP changes. The mass flow variation coefficient, measured in experimental tests, ranged from 6.32 to 1...

Physical Review Letters, 2004

We determine the reversible folding-unfolding of the C-terminal (41-56) fragment of protein G as ... more We determine the reversible folding-unfolding of the C-terminal (41-56) fragment of protein G as a function of density and temperature using replica exchange molecular dynamics simulations. We employ a total of 253 replicas, covering the temperature range between 320 and 515 K and the density range between 0:96 and 1:16 g cm ÿ3. Using the root mean square deviation from the folded structure as a quantitative measure, we are able to obtain the fraction of folded states, and can thus establish the free energy difference between the folded and the unfolded states of the protein fragment as a function of temperature and pressure. For the pressure denaturation the weakening of the hydrophobic interaction between the bulky side chains is found to be crucial at lower temperatures, leading to an apparent destabilization of the folded backbone structure at elevated pressures.

Journal of Computing and Information Technology, 2000

The problem of jointly scheduling both hard deadline periodic tasks and soft aperiodic tasks has ... more The problem of jointly scheduling both hard deadline periodic tasks and soft aperiodic tasks has been the subject of considerable research in real-time systems. One of the most widely accepted solutions for this problem are slack stealing algorithms. However, these algorithms are rather impractical, since they all imply a considerable scheduler overhead. This paper faces the overhead problem by introducing a complete hardware architecture that implements slack stealing in hardware using an optimal algorithm redesigned to be implemented efficiently in hardware. The proposed solution is a circuit that behaves as a kind of sophisticated interrupt controller taking the task workload and the interrupts as inputs, and providing the highest priority task to be executed in the CPU. From the point of view of hardware design, the algorithm involves two main problems: first, to select the highest priority task at every moment and, second, to locate a set of slack gaps in a real-time computation. Locating slack gaps in a real-time computation is a problem that requires to "look forward in time" into the forecast schedule of a given workload. This paper analyses the different approaches for solving this problem and presents a novel architecture to solve it efficiently using a technique based on an event-driven simulation of the future of a real-time computation. A timing analysis of the proposed design is also presented.

Chemical Physics, 2000

Recent breakthroughs in the theory of hydrophobic eects permit new analyses of several characteri... more Recent breakthroughs in the theory of hydrophobic eects permit new analyses of several characteristics of hydrophobic hydration and interaction. Heat capacities of non-polar solvation, and their temperature dependences, are analyzed within an information theory approach, using experimental information available from bulk liquid water. Non-polar solvation in aqueous electrolytes is studied by computer simulations, and interpreted within the information theory. We also study the preferential solvation of small non-polar molecules in heavy water (D 2 O) relative to light water (H 2 O) and ®nd that this revealing dierence can be explained by the higher compressibility of D 2 O. We develop a quasi-chemical description of hydrophobic hydration that incorporates the hydration structure and permits quantummechanical treatment of the solute. Finally, these new results are discussed in the context of hydrophobic eects in protein stability and folding, and of mesoscopic hydrophobic eects such as dewetting.

Catalysis Letters, 1995

The catalytic conversion (dehydration/dehydrogenation) of 2-propanol on a series of CrPO 4-AlPO 4... more The catalytic conversion (dehydration/dehydrogenation) of 2-propanol on a series of CrPO 4-AlPO 4 (CrAlP) catalysts, which were differently prepared and thermally treated at 773–1073 K, has been studied by microcatalytic pulse reactor technique at different temperatures ( ...

Biophysical Journal, 2003

We test molecular level hypotheses for the high thermal stability of a-helical conformations of a... more We test molecular level hypotheses for the high thermal stability of a-helical conformations of alanine-based peptides by performing detailed atomistic simulations of a 20-amino-acid peptide with explicit treatment of water. To assess the contribution of large side chains to a-helix stability through backbone desolvation and salt-bridge formation, we simulate the alanine-rich peptide, Ac-YAEAAKAAEAAKAAEAAKAF-Nme, referred to as the EK peptide, that has three pairs of ''i, i 1 3'' glutamic acid(ÿ) and lysine(1) substitutions. Efficient configurational sampling of the EK peptide over a wide temperature range enabled by the replica exchange molecular dynamics technique allows characterization of the stability of a-helix with respect to heat-induced unfolding. We find that near ambient temperatures, the EK peptide predominately samples a-helical configurations with 80% fractional helicity at 300 K. The helix melts over a broad range of temperatures with melting temperature, T m , equal to 350 K, that is significantly higher than the T m of a 21-residue polyalanine peptide, A 21. Salt-bridges between oppositely charged Glu ÿ and Lys 1 side chains can, in principle, provide thermal stability to a-helical conformers. For the specific EK peptide sequence, we observe infrequent formation of Glu-Lys salt-bridges (with ;10-20% probability) and therefore we conclude that salt-bridge formation does not contribute significantly to the EK peptide's helical stability. However, lysine side chains are found to shield specific ''i, i 1 4'' backbone hydrogen bonds from water, indicating that large side-chain substituents can play an important role in stabilizing a-helical configurations of short peptides in aqueous solution through mediation of water access to backbone hydrogen bonds. These observations have implications on molecular engineering of peptides and biomolecules in the design of their thermostable variants where the shielding mechanism can act in concert with other factors such as salt-bridge formation, thereby increasing thermal stability considerably.

Biochemistry, 2010

This study describes the thermodynamic characterization of a Ubq-UIM fusion construct (Ubq-UIM), ... more This study describes the thermodynamic characterization of a Ubq-UIM fusion construct (Ubq-UIM), designed from the ubiquitin-UIM interaction system, to determine whether it exhibits cooperativity of folding. The Ubq-UIM fusion constructs exhibit higher stability than the core Ubq molecule, consistent with the finding that the UIM helix is docked to Ubq. Temperature-induced unfolding profiles of Ubq-UIM were monitored by DSC and far-UV and near-UV CD spectroscopies. Ubq-UIM appears to exhibit cooperative unfolding as indicated by results of global fits of a two-state model to far-and near-UV CD and DSC thermal unfolding data. The cooperativity of Ubq-UIM unfolding was further tested by the amino acid substitutions that selectively stabilize or destabilize Ubq, UIM, and/or the interface. The effects of these substitutions on the thermodynamic properties of Ubq-UIM are described well by a thermodynamic model for cooperativity in proteins. In particular, a substitution that lowered the stability of the Ubq-UIM interface indeed led to a decrease in cooperativity.