Initial development and production of CO2 in colonies of the leaf-cutting ant Atta sexdens during the claustral foundation

Queens in the genus Atta are solely responsible for fungus cultivation and for care of herself and her offspring. Only few studies have investigated their nests in the claustral foundation and it is unknown the production rate of expelled carbon dioxide and/or of oxygen consumption in the initial colonies of leaf-cutting ants. Thus, we have studied the development of 50 initial colonies of Atta sexdens, and production of expelled carbon dioxide under laboratory conditions. The number of eggs was counted one week after nest foundation on the seventh day, the larvae counted on day 28, and the pupae between days 42 and 49. The workers emerged on the 63rd and 70th day. The CO2 concentration increased steeply in the 42nd days (20.60 ± 8.36%) and 49th days (15,37 ± 13,11 %), at 42nd days,  and subsequently returned to lower values, for example, 3.35±2.84% at week seven. The present study is the first to present CO2 emission data in initial nests, in their claustral foundation under laboratory conditions

Flight and Digging Effort in Leaf-cutting Ant Males and Gynes

The nuptial flight and nest digging are high intensity activities which consume body reserves. The flight and digging effort was quantified by measuring the carbohydrate and total lipids content in males and females before and after the nuptial flight, and the queen’s digging effort during the foundation. The digging effort was quantified by experimentally stimulating the queens to dig a nest – one, two or three consecutive times – compared to the queens that did not dig. The colorimetric method was used to determine the soluble carbohydrates and extraction method of immersion was used to determine the total lipids. The results showed significant loss of carbohydrates and total lipids in males and females after the flight. On average the males contained 0.027 mg of soluble carbohydrates before the nuptial flight, and 0.005 mg after the nuptial flight, and the females contained 0.129 mg of soluble carbohydrates before the nuptial flight, and 0.079 mg after the nuptial flight. For the males the percentage of lipids decreased from 5.27±1.07% to 2.60±0.63% and for females from 36.46±4.86% to 32.62% after the nuptial flight. The digging effort of the queen caused a slight reduction in total carbohydrates, it was without digging 0.054 mg, normal digging 0.055 mg, double digging 0.045 mg (decrease of 20,22 %), and triple digging 0.044 mg  (decrease of 20 %) per queen. Based on our results we conclude that the carbohydrate content is the main energetic resource used for the nuptial flight and nest digging, for males and gynes of leaf-cutting ants

Foraging behavior of leaf cutting ants: How do workers search for their food?

Forager ants search for adequate food sources in nature and, after their discovery, decide whether the source is suitable or not for the colony. However, we asked “How do workers seek out the substrate for cultivation of the symbiontic fungus on which they feed? To answer this question, we evaluated the distance traveled by individual workers in the search of food and the distance traveled to return to the nest, as well as the time and velocity necessary for these activities. The results showed that the distance traveled by the leaf cutting ant, Atta sexdens rubropilosa (Linneus, 1758), in the search of food was greater than the distance traveled to return with the substrate to the colony. On the other hand, the mean time and velocity were similar for food search and return to the colony. These results support the hypothesis of information transfer, according to which the worker needs to return to the nest at the beginning of foraging to transfer information to other workers and thus to establish the process of worker ant foraging. It can be concluded that workers travel large distances in a random manner until finding their substrate, but the return to the nest is efficient considering the shorter distance traveled.

Mandibles of Leaf-Cutting Ants: Morphology Related to Food Preference

Feed adaptation is crucial for the ecological success of animals, which explore specific or varied resources according to the suitability of the selected feature. We hypothesized that the mandibles of leaf-cutting ants exhibit a greater degree of specialization because of the specific food preference of some species. The objective of this study was to highlight possible morphological differences between the mandibles of leaf-cutting ants of the genus Atta related to the food preference of the species, i.e., to investigate the morphofunctionality of mandibles in conjunction with a study of the leaf anatomy of plants selected. A detailed description of the mandibles of workers of the grass-cutting ant Atta bisphaerica and of the leaf-cutting ant Atta sexdens rubropilosa was provided, and the anatomy and chemical composition of the plant material foraged by these species were investigated. For morphometric analysis, 50 individuals of each of the four size classes were dissected for removal of the right mandible and one sample of each caste was processed for scanning electron microscopy. The Atta species had a similar mandibular morphology and differences were only observed between species and among castes, demonstrating the clear specialization of workers. Together with the anatomical study of the foraged plant material, the results indicate a high abundance of lignified cells in grasses, permitting to infer that the foraging and processing of these plants can lead to differences in behavioral acts during their preparation and incorporation in the fungus garden. We accept the hypothesis of morphofunctionality in view of the mandibular morphology observed.

Analysis of Student Performance Data from a Computer Architecture and Organization Course

Some known problems in the literature are the lack of interest and difficulty ofstudents in Computer Architecture and Organization courses. We analyzed the students' performance in tests and semipresential learning activities in three editions of Introduction to Computer Architecture course from the Computer Engineering program of the Federal University of Pampa. We also analyzed the National High School Exam grades of these students, by knowledge area. The purpose of this study is to identify, through analytical processes using data from the course and grades of the NHSE, the most influential factors in the students’ first and final grades and subsidize the proposal of effective actions to solve the problem of high percentages of students’ failure

Sistema de informação gerencial para o Programa de Iniciação Científica (ProIC) da Universidade de Brasília (UnB)

Monografia (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2013.A implementação do Sistema de Informação Gerencial para o Programa de Iniciação Científica (ProIC) da Universidade de Brasília (UnB) demanda uma abordagem diferente para o desenvolvimento de um sistema de Banco de Dados que rode em um servidor Web. A Inteligência de Negócios é um conceito fundamental para o desenvolvimento de um Armazém de Dados, pois determina que deve-se buscar a melhor solução possível para uma certo tipo de problema. Por meio da modelagem multidimensional, pode-se implementar um Armazém de Dados que garanta buscas com boa qualidade. Através de uma Ferramenta que interpreta Processos Analíticos Online, podem ser construídos vários objetos (relatórios, gráficos, tabelas) importantes para uma análise robusta destes dados. A Plataforma Pentaho é formada pelas ferramentas necessárias para a construção de um sistema de Armazém de Dados, dando suporte a implementação de todas as etapas necessárias como a construção do modelo multidimensional, o processo de extração, transformação e carga, a criação de cubos analíticos e geração de relatórios Ad-Hoc. ___________________________________________________________________________ ABSTRACTThe Implementation of Management Information System for the Scientific Initiation Program at University of Brasilia (UnB) demands a different approach to the development of a database system that runs on a Web server. The Business Intelligence is a fundamental concept to the development of a Data Warehouse because it determines the necessity of finding the best possible solution for a certain type of problem. Through multi- dimensional modeling is implemented a Data Warehouse that guarantees querys with good quality. Through a Online Process Analytical Tool, can be built multiple objects (reports, graphs, tables) that is important for a robust analysis of a data. The Pentaho Platform is formed by the necessary tools for the construction of a data warehouse system, supporting the implementation of all the steps required to build the multidimensional model, implementation extraction, transformation and loading process, creation of analytical cubes and generation of Web Ad-Hoc Query Reports

O financiamento externo da política educacional no Paraná (2011-2017)

The present article aims to analyze the political, ideological, financial and educational conditionalities for the financing of educational policy presented by the World Bank in the documents and contracts on the Paraná Multi-sector Development Project implemented in the state during Carlos Alberto Richa’s tenure (2011 - 2017). For the development of this research, a search was made on the Capes website of Theses and Dissertations Catalog and in the page of the Secretary of State's Planning and General Coordination of Paraná, where the Portuguese version of the necessary agreements and manuals was found. Among the documents used to analyze the part of the financing of the Paraná Multi-sector Development Project are: Loan agreement number 8201- BR; the periodic reports and the Project Operational Manual in volumes 1 and 4. We understand that international organizations, especially the Paraná Multi-sector Development Project and the World Bank, have dictated what state education should be like. Therefore, few resources are allocated to the educational area, when compared to other sectors. The documents of the Project have emphasized the effectiveness and quality of the educational system.O presente artigo busca examinar as condicionalidades políticas, ideológicas, financeiras e educacionais para o financiamento da política educacional, apresentadas pelo Banco Mundial nos documentos e nos contratos do Projeto Multissetorial para o Desenvolvimento do Paraná implementado no estado, no período dos governos de Carlos Alberto Richa (2011 – 2017). Para o desenvolvimento desta pesquisa, realizou-se uma busca no Banco de Teses e Dissertações da Capes e na página da Secretaria de Planejamento e Coordenação Geral do Governo do Paraná, em que foi encontrada a versão em português dos contratos e manuais necessários. Entre os documentos usados para analisar a parte do financiamento do Projeto Multissetorial para o Desenvolvimento do Paraná estão: o contrato de empréstimo número 8201- BR; os relatórios periódicos e o Manual operativo do Projeto nos volumes 1 e 4. Compreendemos que os organismos internacionais, especialmente o Projeto Multissetorial para o Desenvolvimento do Paraná e o Banco Mundial, têm ditado como deve ser a educação do estado. Notamos, assim, que poucos recursos são destinados à área educacional, caso comparada a outros setores. Percebemos, ademais, que os documentos do Projeto têm dado ênfase na eficácia e na qualidade do sistema educacional

Do Atta sexdens rubropilosa workers prepare leaves and bait pellets in similar ways to their symbiotic fungus?

Leaf-cutting ants rely on the obligate symbiosis with a fungus, Leucoagaricus gongylophorus, on which they feed. This fungus garden is maintained preferentially with green leaves in combination with other tissues of plant origin. The nutritional composition of this symbiotic relationship is extremely beneficial for the colony, representing the main food source for larvae and an important food component of adult workers. The objective of this study was to observe the behavioral repertoire of Atta sexdens rubropilosa during the preparation and incorporation of two different substrates, leaves and bait pellets, as well as the participation of each caste in these processes this process. The first substrate offered to the colonies were Citrus sp. leaves cut into disks and the second were pellets of citrus pulp bait formulated without the active ingredient. The observations were made under a stereomicroscope and were started when the first portion of the substrate offered was carried to the fungus garden. The behaviors executed during preparation and incorporation of the leaf disks, and subsequently of the bait pellets, were recorded using three colonies, with six repetitions of 5 and 7 hours per colony, respectively. Eight behavioral acts were recorded for the three castes found, irrespective of the substrate processed by the workers. Licking was the most frequently executed behavioral act, which occurred throughout the observation period, regardless of the substrate offered. Gardeners and generalists were the castes most engaged in the execution of this behavior. Considering the large number of individuals involved in the execution of this task, it can be concluded that this behavior is important for dispersion of the active ingredient and contamination of workers inside the colony.

Application of the Minimum Quantity Lubrication (MQL) technique in the plunge cylindrical grinding operation

Precision cylindrical grinding is used extensively in the manufacture of precision components in the metal-mechanical industry in general. Modern CNC grinding machines have improved this process with respect to the positioning and rigidity of the machine-workpiece-tool system, allowing the production of high precision parts with low dimensional tolerances. Besides the difficulties inherent to the process, awareness has grown in recent years regarding the environmental issues of cutting fluids. As a response, the industry has begun to seek alternative lubrication and cooling methods. Among the various existing techniques, Minimum Quantity Lubrication (MQL) has been considered as an alternative. This technique can be understood as a combination of conventional lubrication and cooling methods and dry machining, in which a small quantity of lubricating oil mixed with compressed air flow is delivered in the wheel-workpiece interface. The MQL technique is already widely employed in machining processes with tools of defined geometry (e.g. turning), in which produces very satisfactory results. However, the MQL technique has been little explored in grinding processes (non-defined tool geometry), in which the really effective heat removal methods are required due to the frictional heat generation in the grinding zone. Consequently, the aim of this study was to evaluate the plunge cylindrical internal grinding operation when using the MQL technique and the conventional cooling method. Roughness and roundness were the outputparameters. As a result, it was found that the best values of roughness Ra were obtained with the conventional lubrication method. The MQL technique applied as proposed was not able to flush the chips away from the grinding zone, leading to the highest Ra values. No significant differences were detected among the cooling methods when analyzing the roundness results. The workpiece fixture method selected was responsible for the overall unsatisfactory results.(FAPESP) São Paulo Research Foundatio

Leaf-Cutter Ants and Microbial Control

The attini tribe comprises fungusgrowing ants, such as the basal Apterostigma and other more specialized genera, including the higher attine and the ones that cut the fresh plant tissue (Atta and Acromyrmex), maintaining an obligatory mutualistic relation with the fungus Leucoagaricus gongylophorus, which serves as a food source for the ants. Leaf-cutter ants are considered agriculture pests and populate the soil, a rich environment, especially due to the presence of several microorganisms. Some of these microorganisms are natural enemies that may cause epizootics (quickly spreading opportunistic diseases). Such defence strategies include polyethism, that is, division of labor among the individuals. The older ants take on the responsibility of foraging, as their integument is harder and heavily sclerotized, serving as a protective barrier against pathogens (including bacteria and antagonistic fungi). The younger ants, whose metapleural glands synthetize important secretions to eliminate and control microorganisms that could attack the colony fungus garden and the immature (larvae and pupae), remain inside the colony cultivating symbiont fungi. The sum of the survival strategies of ants in general, including social immunity and nest-cleaning behavior, represents a barrier for the application of biological control programs, mainly microbial ones