697 research outputs found
Transferring cash benefits through the banking sector in Colombia
This paper reviews the experience in transacting payments through the commercial banking system, to beneficiaries in Colombia's"Familias en Accion"program. The story told will be useful to those trying to solve the operational problem of moving cash, cost-effectively to large numbers of beneficiaries in social assistance, or similar programs. It shows the options considered, their advantages, disadvantages, and costs. Though some of the details may be specific to the country, and program, the approach to the analysis is broadly applicable.Banks&Banking Reform,Municipal Financial Management,Financial Intermediation,Financial Crisis Management&Restructuring,Health Monitoring&Evaluation
Aplicación de fertilizantes de liberación controlada al establecimiento de Pinus radiata en Valdivia
Thiers, O.; Gerding, V. Universidad Austral de Chile, Instituto de Silvicultura. Casilla 567, Valdivia, Chile.
Leiva, F. Centro Experimental Forestal CEFOR, Universidad Austral de Chile. Casilla 567, Valdivia, Chile.Se evaluó el efecto de fertilizantes de liberación controlada (FLC) (Basacote® Plus 3M, 6M, 9M, y Starter; 10 a 20 g planta-1) en el período de establecimiento de plantaciones de Pinus radiata. Se instaló un ensayo con FLC y una mezcla de fertilizantes hidrosolubles (fertilización tradicional, 87 g planta-1) en tres sitios de la comuna de Valdivia, sobre suelos rojo arcillosos de la serie Los Ulmos (Typic Palehumult). Luego del primer año de evaluación los FLC y la fertilización tradicional permitieron crecimientos mayores (P 90 %) con y sin ellos. Los valores promedio en los mejores tratamientos alcanzaron: 70±16 cm (H), 16±4 mm de diámetro de cuello (DAC) y 194±12 cm3 de factor de producción (F = DAC2xH). La ganancia promedio de los árboles con FLC fue de 12 a 36 % en H y en DAC, y de 68 a 154 % en FP. La proporción de biomasa radicular (18 %) no fue modificada con las fertilizaciones. Los tratamientos con FLC presentaron ventajas operativas y de costos con respecto a la fertilización tradicional.Con aporte de COMPO AGRO Chile y CEFOR-UACh
Birnbaum–Saunders autoregressive conditional duration models applied to high-frequency financial data
Modern financial markets now record the precise time of each stock trade, along with price and volume, with the aim of analysing the structure of the times between trading events—leading to a big data problem. In this paper, we propose and compare two Birnbaum–Saunders autoregressive conditional duration models specified in terms of time-varying conditional median and mean durations. These models provide a novel alternative to the existing autoregressive conditional duration models due to their flexibility and ease of estimation. Diagnostic tools are developed to allow goodness-of-fit assessment and to detect departures from assumptions, including the presence of outliers and influential cases. These diagnostic tools are based on the parameter estimates using residual analysis and the Cook distance for global influence, and different perturbation schemes for local influence. A thorough Monte Carlo study is presented to evaluate the performance of the maximum likelihood estimators, and the forecasting ability of the models is assessed using the traditional and density forecast evaluation techniques. The Monte Carlo study suggests that the parameter estimators are asymptotically unbiased, consistent and normally distributed. Finally, a full analysis of a real-world financial transaction data set, from the German DAX in 2016, is presented to illustrate the proposed approach and to compare the fitting and forecasting performances with existing models in the literature. One case related to the duration time is identified as potentially influential, but its removal does not change resulting inferences demonstrating the robustness of the proposed approach. Fitting and forecasting performances favor the proposed models and, in particular, the median-based approach gives additional protection against outliers, as expected
Breakdown of biomass for energy applications using microwave pyrolysis: A technological review
The agricultural industry faces a permanent increase in waste generation, which is associated with the fast-growing population. Due to the environmental hazards, there is a paramount demand for generating electricity and value-added products from renewable sources. The selection of the conversion method is crucial to develop an eco-friendly, efficient and economically viable energy application. This manuscript investigates the influencing factors that affect the quality and yield of the biochar, bio-oil and biogas during the microwave pyrolysis process, evaluating the biomass nature and diverse combinations of operating conditions. The by-product yield depends on the intrinsic physicochemical properties of biomass. Feedstock with high lignin content is favourable for biochar production, and the breakdown of cellulose and hemicellulose leads to higher syngas formation. Biomass with high volatile matter concentration promotes the generation of bio-oil and biogas. The pyrolysis system's conditions of input power, microwave heating suspector, vacuum, reaction temperature, and the processing chamber geometry were influence factors for optimising the energy recovery. Increased input power and microwave susceptor addition lead to high heating rates, which were beneficial for biogas production, but the excess pyrolysis temperature induce a reduction of bio-oil yield
Birnbaum-Saunders spatial modelling and diagnostics applied to agricultural engineering data
Applications of statistical models to describe spatial dependence in geo-referenced data are widespread across many disciplines including the environmental sciences. Most of these application assume that the data follow a Gaussian distributions. However, in many of them the normality assumption, and even a more general assumption of symmetry, are not appropriate. In non-spatial applications, where the data are uni-modal and positively skewed, the Birnbaum-Saunders distribution has excelled. This paper proposes a spatial log-linear model based in the Birnbaum-Saunders distribution. Model parameters are estimated using the maximum likelihood method. Local influence diagnostics are derived to assess the sensitivity of the estimators to perturbations in the response variable. As illustration, the proposed model and its diagnostics are used to analyse a real-world agricultural data-set, where the spatial variability of phosphorus concentration in the soil is considered- which is extremely important for agricultural management
¿Qué está haciendo el científico? : análisis de la actividad científica descrita por alumnos secundarios chilenos de 11° y 12° grado de distintos tipos de establecimientos educacionales
Con el objetivo de conocer la representación de estudiantes secundarios chilenos de distintos tipos de establecimientos acerca de los científicos y la actividad que estos realizan, se aplicó a una muestra de 438 estudiantes de 11° y 12° grado el Draw-a-Scientist-Test, en la versión de Türkmen (2008). En ella, los alumnos son invitados a describir de manera escrita la actividad que realiza el científico que dibujaron. Dichas narraciones fueron analizadas en función de los procesos científicos relatados, propósitos y consecuencia de la actividad descrita. Los procesos científicos más frecuentemente mencionados fueron “experimentar” y “observar”. “Formular modelos”, proceso fundamental en la actividad científica, prácticamente no fue mencionado. En relación a propósitos y consecuencias la mayoría de los alumnos tiene una imagen positiva de la actividad científica
Patrón de comportamiento tipo A, ira y enfermedades cardiovasculares (ECV) en población urbana chilena
Diaz, EM (Moyano Diaz, Emilio)1; Icaza, G (Icaza, Gloria); Mujica, V (Mujica, Veronica); Nunez, L (Nunez, Loreto); Leiva, E (Leiva, Elba); Vasquez, M (Vasquez, Marcela); Palomo, I (Palomo, Ivan)A worldwide raise in the number of cardiovascular disease (CVD) and the existence of a higher percentage in Maule (Chile) than the national media, and increased attention in the analysis of psychological factors motivate to analyze the Type A Behavior Pattern (TABP) and anger in relation to CVD. The sample was 1007 adults between 18 and 74 years old (citizens of Talca, Chile), mostly women. They provided information about their demographic details, eating habits and lifestyle, answered the Novaco's Anger inventory and the Retiro Scale of Type A Behavior (RSTAB), and also were taken measurements like weight, body mass index and blood pressure and blood tests related to risk factors to traditional cardiovascular diseases. The results show Overall, that the participants appear highly sedentary (79.9%) with relatively high levels of tabaquism (53.6%), and hypercholesterolemia (44.5%), overweight (40.7%) and obesity (32.6%). A quarter of the sample also presents hyperglycemic indexes, hypertension and TABP unequally distributed by sex. The absence of PCTA (or PCTB presence) appeared mostly associated with traditional cardiovascular risk factors (CRF). Regarding anger, women present more high than men (2.1% against 0.3%; c(2)(3) = 27.99,p<.0001), decreasing for both sexes with age, while also befall stroke by sex
Nonlinear supersymmetry: from classical to quantum mechanics
Quantization of the nonlinear supersymmetry faces a problem of a quantum
anomaly. For some classes of superpotentials, the integrals of motion admit the
corrections guaranteeing the preservation of the nonlinear supersymmetry at the
quantum level. With an example of the system realizing the nonlinear
superconformal symmetry, we discuss the nature of such corrections and
speculate on their possible general origin.Comment: 11 page
Is there life inside black holes?
Bound inside rotating or charged black holes, there are stable periodic
planetary orbits, which neither come out nor terminate at the central
singularity. Stable periodic orbits inside black holes exist even for photons.
These bound orbits may be defined as orbits of the third kind, following the
Chandrasekhar classification of particle orbits in the black hole gravitational
field. The existence domain for the third kind orbits is rather spacious, and
thus there is place for life inside supermassive black holes in the galactic
nuclei. Interiors of the supermassive black holes may be inhabited by
civilizations, being invisible from the outside. In principle, one can get
information from the interiors of black holes by observing their white hole
counterparts.Comment: 11 pages, 5 figures; references adde
Discussion of “Birnbaum‐Saunders distribution: A review of models, analysis, and applications” and a novel multivariate data analytics for an economics example in the textile industry
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