Density functional theory (dft) method and its aplications in materials science

Una breve explicación de lo que es la Teoría del Funcional de la Densidad DFT se presenta en este trabajo. Se exhiben sus ventajas y desventajas. Cómo es mucho más fácil de convertir una función de onda que trata de un problema de muchos cuerpos, 3N variables, a uno con sólo 3 variables, así como, por qué es necesario el uso de aproximaciones. Se demuestra el método de Kohn-Sham como las aplicaciones más comunes de la DFT, y la forma en que se puede implementar de diferentes maneras dependiendo de lo que va a ser investigado. Una breve descripción del formalismo de la teoría también se presenta y tratamos de enaltecer los múltiples usos y aplicaciones de la DFT

The Effect of an Acidified-Gypsum Mixture on Broiler Litter Urease-Producing Bacteria and Nitrogen Mineralization

Broiler chicken (Gallus gallus domesticus) production is one of the largest agricultural sectors in the state of Georgia. Broiler litter produced by broiler facilities is rich in organic nitrogen (N), specifically urea, which can be mineralized by poultry litter urease-producing bacteria (PLUP) forming ammoniacal-N (NH3/NH4+). A large portion of NH3/NH4+ can be lost as ammonia (NH3) gas, which negatively impacts bird health and profitability. The release of NH3 from litter is strongly influenced by the pH of the litter. Flue-gas desulfurization gypsum (FGDG) has been suggested as a potential amendment to reduce NH3 volatilization from broiler litter due to the pH buffering capacity of calcium carbonate (CaCO3) precipitation. However, its effect on litter pH is not as pronounced as acidifying agents, such as aluminum sulfate (alum). The main objective of the present study was to develop an acidified-FGDG amendment that has a more pronounced effect on litter pH and NH3 volatilization than FGDG alone. We conducted a 33-d incubation in which litter pH, NH3 volatilization, PLUP-ureC gene abundance, and CaCO3 precipitation were measured. Treatments in the study included: broiler litter (control) (BL), broiler litter + 20% FGDG (BL+FGDG), broiler litter + FGDG-alum mixture (BL+FGDG+A6), broiler litter + 6% alum (BL+A6), and broiler litter + 10% alum (BL+A10). Our results indicated that ammending broiler litter with the FGDG+alum decreased litter pH (0.68 pH units) and PLUP-ureC gene abundance (\u3e 1 log) compared to FGDG alone and the control (p \u3c 0.05). This led to a 25% decrease in cumulative NH3 loss after 33 d. The addition of FGDG alone did not have an effect on litter pH (p = 0.36) or cumulative NH3 loss (p = 0.29) due to a lack of significant CaCO3 precipitation. Alum 6% and 10% were the most effective amendment for reducing cumulative NH3

Use of a Nitrogen Leaching Model as a Design Criterion for Land Application of Waste Water

Proceedings of the 1991 Georgia Water Resources Conference, March 19-20, 1991, Athens, Georgia.Land application is a viable alternative to conventional waste treatment plants for environmentally safe disposal of liquid wastes. To ensure protection of the state's water resources, guidelines have been established specifying variables that should be considered in design of land application systems. These guidelines also specify maximum levels of hydraulic loading, heavy metals in the soil, and N concentration in water percolating through the soil (Georgia EPD, 1986). Any of these three factors may limit the annual amount of waste applied to a site. For hydrologic loading, the design criteria are based on monthly net precipitation (precipitation - potential evapotranspiration) and soil properties that influence the hydrology of the soil. The maximum monthly rate of waste application is determined by the month in which net precipitation plus monthly waste addition is maximal. Total net precipitation plus waste additions during this month cannot exceed the soil's capacity to transmit the liquid without ponding and runoff. If nitrogen content of the waste is such that limits on soil percolate N concentration will be exceeded with application rates which meet hydrologic loading criteria, size of spray field area is determined based on an annual rather than monthly N balance. The major sink for N considered in design of land application systems is plant uptake. Rather than being uniform throughout the year as suggested by the current practice of using annual values in the system design, crop growth and associated N uptake is cyclic, and depending on the crop or crops growing, periods of plant dormancy or reduced growth may occur when little or none of applied N is being removed from the soil. Thus, during these periods N applied may move quickly through the soil profile and potentially to shallow ground water. This may be especially true in Georgia where warm temperatures promote rapid nitrification and the retentive capacity of the soils for ammonium is low. Models to predict nitrate leaching through soils under different climatic and management regimes are currently available and improved versions are steadily being released. These models simulate N uptake by crops, N transformations such as nitrification, denitrification, and volatilization, and water and nitrate movement through the soil, and offer the opportunity to evaluate the effectiveness of N removal by land treatment under various management, climatic, and soil conditions. The objective of this study was to use a N leaching model to evaluate the soil N balance under different soil and management conditions for a hypothetical land application system sized by current design criteria.Sponsored by U.S. Geological Survey, Georgia Department of Natural Resources, the University of Georgia, Georgia State University, and Georgia Institute of Technology.This book was published by the Institute of Natural Resources, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of the Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1984 (P.L. 98242). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia or the U.S. Geological Survey or the conference sponsors

Fragmentos da trajetória de um pintor na transição do século XIX para o XX: Pedro Weingärtner e suas redes sociais

O presente artigo trata-se de um recorte relacionado aos aspectos biográficos do artista gaúcho Pedro Weingärtner, especialmente no que tange à sua trajetória profissional. Busca-se compreender elementos da trajetória profissional do artista atentando para a forma que Weingärtner soube articular suas relações e redes sociais na tentativa de manutenção e fomento de sua carreira, obtendo, dessa forma, concessão de bolsa de estudos na Europa, alguns amigos “mecenas” que o ajudaram no início da carreira e uma representatividade bastante positiva nos periódicos brasileiros. Pedro Weingärtner passou boa parte da sua vida na Europa, mas foi no Brasil que teve o reconhecimento de seu trabalho. Nesse caso, esta pesquisa pretende investigar parte da trajetória profissional do artista, bem como aspectos de sua vida pessoal que colaborem para mapear dimensões da sua carreira, na transição do século XIX para o XX

Quijote del Centenario 1605-1905 (láminas) - Tomo 1

Colección de 8 tomos, 4 de texto y 4 de láminas, editados en Madrid. Contiene 689 láminas de J. Jiménez Aranda, y 111 de Alpéríz, Bilbao, García Ramos, Jiménez (Luis), L. Cabrera, Moreno Carbonero, Sorolla, Sala y Villegas, con un juicio crítico de la obra, de D. José R. Mélída.Material digitalizado en Sedici gracias a la colaboración de la Biblioteca Pública de la UNLP.Listado de tomos que componen la obra: - Tomo 1 (texto): http://sedici.unlp.edu.ar/handle/10915/82644 - Tomo 2 (texto): http://sedici.unlp.edu.ar/handle/10915/82645 - Tomo 3 (texto): http://sedici.unlp.edu.ar/handle/10915/82647 - Tomo 4 (texto): http://sedici.unlp.edu.ar/handle/10915/82649 - Tomo 1 (láminas): http://sedici.unlp.edu.ar/handle/10915/82651 - Tomo 2 (láminas): http://sedici.unlp.edu.ar/handle/10915/82653 - Tomo 3 (láminas): http://sedici.unlp.edu.ar/handle/10915/82655 - Tomo 4 (láminas): http://sedici.unlp.edu.ar/handle/10915/82657Biblioteca Públic

Testing the EPIC Richards submodel for simulating soil water dynamics under different bottom boundary conditions

AbstractMost biogeochemical models simulate water dynamics using the tipping bucket approach, which has been often found to be too simplistic to represent vadose zone dynamics adequately under shallow groundwater conditions. Recently, a solution to the Richards equation using the Mualem–van Genuchten model (Rich‐vGM) has been added into the EPIC (Environmental Policy Integrated Climate) model to address this shortfall. Its performance was tested using lysimeters operating under free drainage (FD) and at a shallow water table (60‐ [WT60] and 120‐cm depth [WT120]). Model accuracy was also compared with the upgraded tipping bucket‐based method implemented into EPIC (the variable saturation hydraulic conductivity method [VSHC]). Soil water content (SWC) data were split into calibration and validation subsets. Model evaluation also included annual evapotranspiration (ET), percolation (PRK), and upward water movements to assess underlying soil water balance factors. The submodels provided accurate and similar results upon comparison with SWC measures under FD (Nash–Sutcliffe coefficient [NSE] = 0.26 and 0.61 using VSHC and Rich‐vGM, respectively). The Rich‐vGM model accurately reproduced observed SWC and ET (e.g., NSE = 0.70 and percentage bias [PBIAS] = −3.7% for WT120, respectively) although it slightly overestimated PRK (PBIAS = 47.8%, on average). Instead, VSHC proved unable to correctly simulate shallow groundwater conditions (e.g., NSE = −1.85 for WT60 SWC). Under shallow groundwater conditions, the Rich‐vGM method is recommended, despite the additional data required and the need to define the bottom boundary conditions according to water table fluctuations. In conclusion, the Richards solver introduced and tested in EPIC improved the model's ability to represent complex biophysical and biogeochemical processes in terrestrial ecosystems associated with the hydrological balance

A microfluidics and agent-based modeling framework for investigating spatial organization in bacterial colonies: The case of Pseudomonas Aeruginosa amd H1-type VI secretion interactions

The factors leading to changes in the organization of microbial assemblages at fine spatial scales are not well characterized or understood. However, they are expected to guide the succession of community development and function toward specific outcomes that could impact human health and the environment. In this study, we put forward a combined experimental and agent-based modeling framework and use it to interpret unique spatial organization patterns of H1-Type VI secretion system (T6SS) mutants of P. aeruginosa under spatial confinement. We find that key parameters, such as T6SS-mediated cell contact and lysis, spatial localization, relative species abundance, cell density and local concentrations of growth substrates and metabolites are influenced by spatial confinement. The model, written in the accessible programming language NetLogo, can be adapted to a variety of biological systems of interest and used to simulate experiments across a broad parameter space. It was implemented and run in a high-throughput mode by deploying it across multiple CPUs, with each simulation representing an individual well within a high-throughput microwell array experimental platform. The microfluidics and agent-based modeling framework we present in this paper provides an effective means by which to connect experimental studies in microbiology to model development. The work demonstrates progress in coupling experimental results to simulation while also highlighting potential sources of discrepancies between real-world experiments and idealized models

Video frame prediction of microbial growth with a recurrent neural network

The recent explosion of interest and advances in machine learning technologies has opened the door to new analytical capabilities in microbiology. Using experimental data such as images or videos, machine learning, in particular deep learning with neural networks, can be harnessed to provide insights and predictions for microbial populations. This paper presents such an application in which a Recurrent Neural Network (RNN) was used to perform prediction of microbial growth for a population of two Pseudomonas aeruginosa mutants. The RNN was trained on videos that were acquired previously using fluorescence microscopy and microfluidics. Of the 20 frames that make up each video, 10 were used as inputs to the network which outputs a prediction for the next 10 frames of the video. The accuracy of the network was evaluated by comparing the predicted frames to the original frames, as well as population curves and the number and size of individual colonies extracted from these frames. Overall, the growth predictions are found to be accurate in metrics such as image comparison, colony size, and total population. Yet, limitations exist due to the scarcity of available and comparable data in the literature, indicating a need for more studies. Both the successes and challenges of our approach are discussed

Evaluation of a Small, In-field Runoff Collector

Proceedings of the 1999 Georgia Water Resources Conference, March 30 and 31, Athens, Georgia.Increased environmental concern about surface water pollution has heightened the need for small, in-field runoff collectors to assess the impact of land management practices without altering the landscape. We modified a surface flow sampler designed for sheet flow in Coastal Plain soils. Modifications were made to accommodate steep slopes (3 to 15% ), large flow rates, and channelized flow which are common in the Southern Piedmont. The runoff collector consists of two sample splitters (10x and 100x) and two sample collectors. Runoff collector performance was evaluated in the laboratory to determine percent flow captured by 10x and 100x splitters relative to flow rate and slope. Average flow captured on a 5% slope was 10.3% for 10x and 1.8% for the l00x. When the slope was increased to 12% the percent flow capture also increased slightly, 10.4% for l0x and 2.3% for l00x. It was determined that the small, in-field runoff collector captures runoff volumes at specific rates at fairly consistent ratios.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202 with partial funding provided by the U.S. Department of Interior, geological Survey, through the Georgia Water Research Insttitute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors

Analysis of a superbolide from a Damocloid observed over Spain on July 13, 2012

A superbolide with an estimated absolute magnitude of-20±1was seen on 2012 July 13 over the centre and south of Spain. This extraordinary event, which was witnessed by numerous casual observers, was recorded in the framework of the continuous fireball monitoring and meteor spectroscopy campaign performed by the SPanish Meteor Network (SPMN). Thus, because of optimal weather conditions, the bolide was imaged from 10 meteor observing stations. Here we present the analysis of this magnificent event, which is the brightest fireball ever recorded by our team. The atmospheric trajectory of the bolide and the orbit in the Solar system of the parent meteoroid were obtained. The emission spectrum produced during the ablation of this particle is also discussed.We found that the meteoroid, which was following a Halley Type Comet orbit, was depleted in Na and had a tensile strength one order of magnitude higher than that corresponding to typical cometary materials. By means of orbital analysis tools we have investigated the likely parent body of this particle and the results suggest that the progenitor is a damocloid. The impact area of the hypothetical remnants of the meteoroid is also given and a search for meteorites was performed, but none was found.Ministerio de Ciencia e Innovación AYA2009-13227 AYA2009-06330-E AYA2011-26522Junta de Andalucía P09-FQM-455