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Formulations and heuristic for the long-term preventive maintenance order scheduling problem.
No full textThis paper studies the long-term preventive maintenance order scheduling problem (LTPMOSP). The problem consists of deciding which maintenance should be scheduled, assigning each maintenance simultaneously to a team and a machine over the planning horizon, and determining when each maintenance should be performed. The goal of the problem is to minimize the number of teams activated and the sum of penalties for maintenance not scheduled. This paper presents two new formulations for the problem, where the first formulation is based on time-indexed variables, and the second formulation combines time-indexed variables with precedence variables. Furthermore, to solve large-size instances, an algorithm based on the GRASP metaheuristic is proposed. The results of the computational experiments show that the new formulations significantly outperform the literature formulation by finding new optimal solutions for some instances with up to 600 maintenance orders. The second formulation stands out by finding a more significant number of optimal solutions. The results also show a superiority of the GRASP algorithm over heuristic methods in the literature, generating better upper bounds in expressively less time, resulting in a schedule with a greater percentage of maintenance planned to be performe
Potencial pedagógico de espaços não formais : o Parque Natural Municipal das Andorinhas como local para praticar a educação ambiental crítica com alunos de uma escola pública.
No full textPrograma de Pós-Graduação em Ensino de Ciências. Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto.Esta pesquisa teve como objetivo investigar o potencial pedagógico do Parque Natural Municipal das Andorinhas (PNMA) para práticas de Educação Ambiental com enfoque crítico, subsidiando a elaboração de um Guia Educativo. A metodologia utilizada foi uma abordagem qualitativa do tipo pesquisa participante. Participaram da pesquisa 13 alunos do 2º e 3º anos do ensino médio de uma escola pública de Ouro Preto-MG. Foi realizada uma oficina com três encontros: encontro na escola; visita ao PNMA para atividades e reflexões in loco; encontro na escola para considerações finais. A coleta de dados foi feita por meio de gravação audiovisual, fotos, diário de campo do pesquisador, bilhetes, desenhos e cartas elaboradas pelos alunos durante as atividades propostas na oficina. Para a análise de dados foi utilizada a Análise de Livre Interpretação. Como considerações da pesquisa, os alunos demonstraram, inicialmente, uma compreensão limitada da Educação Ambiental (EA), centrada em ações individuais e desvinculada de contextos mais amplos. No entanto, ao longo dos diálogos e atividades realizadas, foi possível notar que, quando devidamente orientados, eles começaram a estabelecer conexões entre aspectos sociais, históricos e ambientais, evidenciando uma criticidade crescente. Isso reforça a necessidade de abordar a EA de forma mais abrangente, integrando-a às suas realidades, para que estes estudantes possam desenvolver uma visão mais crítica e contextualizada, reforçando o sentimento de pertencimento dos alunos, que se encontra fragilizado. A proposta do produto educacional “Guia Educativo: pensando e praticando Educação Ambiental Crítica no Parque Natural Municipal das Andorinhas”, elaborado a partir desta pesquisa, é explorar a potencialidade do parque e possibilitar uma reflexão crítica sobre a Educação Ambiental utilizando o PNMA, enquanto espaço não formal de ensino.This research aimed to investigate the pedagogical potential of the Andorinhas Municipal Natural Park (PNMA) for Environmental Education practices with a critical focus, supporting the development of an Educational Guide. The methodology used was a qualitative approach of the participatory research type. Thirteen 2nd and 3rd year high school students from a public school in Ouro Preto-MG participated in the research. A workshop was held with three meetings: meeting at school; visit to PNMA for on-site activities and reflections; meeting at school for final considerations. Data collection was done through audiovisual recording, photos, the researcher's field diary, notes, drawings and letters drawn up by the students during the activities proposed in the workshop. Free Interpretation Analysis was used for data analysis. As research considerations, students initially demonstrated a limited understanding of Environmental Education (EE), focused on individual actions and disconnected from broader contexts. However, throughout the dialogues and activities carried out, it was possible to notice that, when properly guided, they began to establish connections between social, historical and environmental aspects, showing a growing criticality. This reinforces the need to approach EE in a more comprehensive way, integrating it into their realities, so that these students can develop a more critical and contextualized vision, reinforcing the students' sense of belonging, which is weakened. The proposal for the educational product “Educational Guide: thinking and practicing Critical Environmental Education in the Andorinhas Municipal Natural Park”, created based on this research, was to explore the potential of the park and enable critical reflection on Environmental Education using the PNMA, as a space non-formal teaching
Avaliação do tratamento concomitante do Canabidiol e medicamentos para a doença de Alzheimer em neurônios HT22 sob toxicidade induzida pelo peptídeo Aβ 25-35.
No full textPrograma de Pós-Graduação em Biotecnologia. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa de Pós Graduação, Universidade Federal de Ouro Preto.A doença de Alzheimer (DA) é a principal doença neurodegenerativa que afeta o sistema
nervoso de idosos em todo o mundo, é caracterizada pela perda progressiva de sinapses e morte
neuronal, resultando em distúrbios neuropsiquiátricos, déficits de memória e comprometimento
das funções cognitivas. As principais características neuropatológicas incluem a presença de
placas senis, formadas pelo acúmulo do peptídeo beta-amiloide (Aβ), e emaranhados
neurofibrilares decorrentes da hiperfosforilação da proteína tau. Esses marcadores são
responsáveis por desencadear uma cascata de eventos celulares danosos, como o estresse
oxidativo, produzindo espécies reativas de oxigênio (EROs) que danificam proteínas, lipídios
e o DNA, culminando em morte neuronal. Atualmente, os tratamentos disponíveis incluem os
anticolinesterásicos e memantina, que oferecem apenas alívio sintomático, sem alterar a
progressão da doença. Nesse sentido, o canabidiol (CBD), um fitocanabinoide não psicoativo
extraído da Cannabis sativa, vem ganhando relevância devido às suas propriedades
neuroprotetoras, anti-inflamatórias e antioxidantes. Essas características sugerem que o CBD
pode influenciar os mecanismos patológicos da doença de Alzheimer e potencialmente
melhorar os efeitos dos tratamentos convencionais quando usados em combinação. Desta
forma, o objetivo deste estudo foi avaliar o efeito da combinação de canabidiol,
anticolinesterásicos e memantina em neurônios HT22 expostos à toxicidade do Aβ 25-35. Os
neurônios HT22 foram cultivados e tratados com memantina, galantamina, donepezil, Aβ 25-35
e CBD isoladamente durante 24 horas. Em seguida, as combinações dos tratamentos foram
testadas para avaliar o efeito combinado dos fármacos e do CBD sobre os danos induzidos pelo
Aβ 25-35. As avaliações foram realizadas por meio de ensaios de metabolismo celular (MTT),
mensuração intracelular de EROs e peroxidação lipídica após 24 horas de tratamento. Os
resultados mostraram que o peptídeo Aβ 25-35 reduziu o metabolismo celular em 32% e
aumentou a produção de EROs e peroxidação lipídica. O CBD isolado demonstrou ser um
potente antioxidante, revertendo esses danos. No entanto, as combinações entre os
medicamentos e o CBD não foram capazes de restaurar completamente os danos causados pelo
Aβ 25-35. Esses achados sugerem que, embora o CBD tenha ação antioxidante significativa
contra os efeitos do peptídeo Aβ, sua combinação com os medicamentos utilizados no
tratamento da DA pode ter um efeito prejudicial.Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder affecting the
nervous system of elderly individuals worldwide. It is characterized by the progressive loss of
synapses and neuronal death, leading to neuropsychiatric disorders, memory deficits, and
cognitive impairment. The primary neuropathological features include the presence of senile
plaques, formed by the accumulation of amyloid-beta (Aβ) peptide, and neurofibrillary tangles
resulting from the hyperphosphorylation of the tau protein. These markers initiate a cascade of
harmful cellular events, such as oxidative stress, producing reactive oxygen species (ROS) that
damage proteins, lipids, and DNA, ultimately leading to neuronal death. Current treatments,
such as cholinesterase inhibitors and memantine, provide only symptomatic relief without
altering the progression of the disease. In this context, cannabidiol (CBD), a non-psychoactive
phytocannabinoid extracted from Cannabis sativa, has garnered attention for its
neuroprotective, anti-inflammatory, and antioxidant properties. These characteristics suggest
that CBD may influence the pathological mechanisms of Alzheimer's disease and potentially
enhance the efficacy of conventional treatments when used in combination. This study aimed
to evaluate the effect of combining cannabidiol, cholinesterase inhibitors, and memantine on
HT22 neurons exposed to Aβ 25-35 toxicity. HT22 neurons were cultured and treated individually
with memantine, galantamine, donepezil, Aβ 25-35, and CBD for 24 hours. Subsequently,
combinations of these treatments were tested to assess the combined effects of the drugs and
CBD on Aβ 25-35-induced damage. Evaluations were conducted using cellular metabolism
assays (MTT), intracellular ROS measurements, and lipid peroxidation after 24 hours of
treatment. The results indicated that Aβ 25-35 reduced cellular metabolism by 32% and increased
ROS production and lipid peroxidation. CBD alone demonstrated potent antioxidant properties,
reversing this damage. However, the drug and CBD combinations were unable to restore the
damage caused by Aβ25-35 fully. These findings suggest that while CBD exhibits significant
antioxidant activity against the effects of the Aβ peptide, its combination with drugs used in
AD treatment may produce adverse effects
The making of the Roman dishonor : elements for understanding the making of bad reputations in (and coming from) Roman Antiquity.
No full textEste trabajo contiene una versión revisada de la conferencia que presentamos como parte del
workshop “Pensar las sociedades antiguas. Formas de estatalidad, poder, dominación y
resistencia” en la Universidad Nacional de Mar del Plata. Desplegamos un panorama de los
trabajos que hemos producido en el ámbito del Laboratorio de Estudios sobre el Imperio Romano
(LEIR), de la Universidad Federal de Ouro Preto, sobre el tema del deshonor en la Roma de fines
de la República e inicios del Principado. Ponemos en evidencia algunos conceptos que hemos
desarrollado para estudiar, por una parte, cómo se representa el deshonor en las fuentes, y, por
otra, cómo fue utilizado como herramienta en la competencia aristocrática. Analizamos así el
deshonor y su producción en la frontera entre la representación/fabricación de tradiciones y la
realidad vivida.This paper is a revised version of the conference that presented at the workshop “Thinking about
ancient societies. Forms of statehood, power, domination and resistance” at the National
University of Mar del Plata. It presents an overview of the work that has been produced at the
Laboratory for the Study of the Roman Empire (LEIR), of the Federal University of Ouro Preto
on the topic of dishonor in Rome at the end of the Republic and beginning of the Principality. We
highlight some concepts that we have developed to study, on the one hand, how dishonor was
represented in the sources, and, on the other hand, how it was used as a tool in aristocratic
competition. We thus analyze dishonor and its production on the border between the
representation/fabrication of traditions and lived reality
Polarização de partículas e interfaces em meios dielétricos e eletrólitos.
No full textPrograma de Pós-Graduação em Ciências – Física de Materiais. Departamento de Física, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto.Interfaces e partículas polarizáveis estão presentes em muitos sistemas de re-
levância na física, química e biologia. Em muitos casos, a polarização dessas
superfícies se deve a uma descontinuidade dielétrica, quando a interface separa
meios lineares com diferentes propriedades ópticas/dielétricas. Apesar de sua
relevância, o estudo da polarização dessas interfaces é ainda incompleto, con-
tendo muitas questões em aberto. Um exemplo simples consiste na interação
entre esferas metálicas em meios eletrólitos ou dielétricos, cuja interação de
curto alcance é ainda debatida na literatura. Entender a interação entre par-
tículas polarizáveis requer, como um primeiro passo, conhecer a forma como
cargas do meio induzem cargas de polarização nessas superfícies. O objetivo do
presente trabalho é o de estudar as cargas de polarização, bem como as distri-
buições iônicas de equilíbrio de eletrólitos ao redor de superfícies polarizáveis,
planas ou esféricas. Para isso, adotamos a teoria clássica de Debye-Hückel, em
combinação com o formalismo das funções de Green no contexto da eletrostá-
tica.Polarizable particles and interfaces are present in a number of systems of rele-
vance in physics, chemistry and biology. In many cases, the surface polarization
is due to a dielectric discontinuity, when the interface separates linear media
with different optical/dielectric properties. In spite of its relevance, the study
of such interfaces is still incomplete, and many open questions still remain. A
simple example consists in the interaction between metallic, spherical surfaces
embedded on either dielectrics or electrolytes, whose short-ranged interaction
is still under intensive debate. Understanding the interactions between these
particles requires, as a first step, knowing how the charges on the media induce
polarized charges on their surfaces. The aim of the present work is to study
such polarization charges, as well as the resulting ionic equilibrium distributi-
ons of electrolytes surrounding polarizing surfaces, of either spherical or planar
shape. To this end, we use the classical Debye-Hückel theory, in combination
with the Green function formalism in electrostatic
Patrimônio gastronômico e gourmetização : a influência dos novos restaurantes no mercado novo de Belo Horizonte.
No full textPrograma de Pós-Graduação em Turismo e Patrimônio. Departamento de Turismo, Escola de Direito, Turismo e Museologia, Universidade Federal de Ouro Preto.Os hábitos e tradições alimentares são parte intrínseca da identidade cultural de uma
sociedade, refletindo não apenas na nutrição, mas também nas relações sociais, valores,
identidade e memórias coletivas. A gastronomia, como expressão máxima destas tradições,
desempenha papel crucial na formação de identidade de uma comunidade, conectando
gerações por meio de sabores e práticas que são transmitidas com o passar dos anos. Contudo,
em um cenário contemporâneo marcado por transformações econômicas e turísticas,
observa-se a emergência de fenômenos como a gourmetização, que ao alterar as
características dos pratos, numa tentativa de diferenciação econômica e criativa, pode
influenciar diretamente a dinâmica sociocultural desses espaços, podendo trazer impactos
positivos e negativos. Neste contexto, a presente dissertação analisa o Mercado Novo de Belo
Horizonte para verificar se ocorre gourmetização nos novos estabelecimentos do mercado.
Este mercado, conhecido por sua riqueza cultural e diversidade gastronômica, tornou-se um
espaço emblemático onde as práticas alimentares se entrelaçam com as transformações
urbanas. Os novos restaurantes serão analisados com base nos restaurantes tradicionais, assim,
adotou-se abordagem exploratória e qualitativa. Conclui-se que, embora a gourmetização não
seja generalizada, ela está presente em certos espaços do Mercado Novo, evidenciando uma
transformação cultural e econômica. Esse movimento atrai novos públicos e valoriza o
patrimônio gastronômico, mas também levanta questões sobre a preservação da memória
social e das tradições locais, gerando uma tensão entre o histórico e o contemporâneo.Food habits and traditions are an intrinsic part of a society's cultural identity, reflecting not
only nutrition but also social relationships, values, identity, and collective memories.
Gastronomy, as the ultimate expression of these traditions, plays a crucial role in shaping a
community's identity, connecting generations through flavors and practices passed down over
the years. However, in a contemporary scenario marked by economic and tourist
transformations, the emergence of phenomena such as gourmetization is observed, which, by
altering the characteristics of dishes in an attempt at economic and creative differentiation,
can directly influence the sociocultural dynamics of these spaces, potentially bringing both
positive and negative impacts. In this context, this dissertation analyzes the Mercado Novo in
Belo Horizonte to verify if gourmetization occurs in the market's new establishments. This
market, known for its cultural richness and gastronomic diversity, has become an emblematic
space where food practices intertwine with urban transformations. The new restaurants will be
analyzed based on traditional ones, adopting an exploratory and qualitative approach. It is
concluded that although gourmetization is not widespread, it is present in certain spaces of
Mercado Novo, highlighting a cultural and economic transformation. This movement attracts
new audiences and enhances gastronomic heritage but also raises questions about the
preservation of social memory and local traditions, creating a tension between the historical
and the contemporary
Alterations in vagal tone are associated with changes in the gut microbiota of adults with anxiety and depression symptoms : analysis of fecal metabolite profiles.
No full textAccumulating evidence suggests that interactions between the brain and gut microbiota significantly impact brain function and mental health. In the present study, we aimed to investigate whether young, healthy adults without psychiatric diagnoses exhibit differences in metabolic stool and microbiota profiles based on depression/anxiety scores and heart rate variability (HRV) parameters. Untargeted nuclear magnetic resonance-based metabolomics was used to identify fecal metabolic profiles. Results were subjected to multivariate analysis through principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), and the metabolites were identified through VIP score. Metabolites separating asymptomatic and symptomatic groups were acetate, valine, and glutamate, followed by sugar regions, glutamine, acetone, valerate, and acetoacetate. The main metabolites identified in high vagal tone (HVT) and low vagal tone (LVT) groups were acetate, valerate, and glutamate, followed by propionate and butyrate. In addition to the metabolites identified by the PLS-DA test, significant differences in aspartate, sarcosine, malate, and methionine were observed between the groups. Levels of acetoacetate were higher in both symptomatic and LVT groups. Valerate levels were significantly increased in the symptomatic group, while isovalerate, propionate, glutamate, and acetone levels were significantly increased in the LVT group. Furthermore, distinct abundance between groups was only confirmed for the Firmicutes phylum. Differences between participants with high and low vagal tone suggest that certain metabolites are involved in communication between the vagus nerve and the brain
Agripina, Cleópatra e Messalina : estratégias retórico-poéticas na representação de mulheres em posições de poder.
No full textPrograma de Pós-Graduação em Letras. Departamento de Letras, Instituto de Ciências Humanas e Sociais, Universidade Federal de Ouro Preto.O objetivo da presente pesquisa é estudar e analisar os retratos e representações de algumas
mulheres em posições de poder (ou de soberania) na Antiguidade, sobretudo durante a época
do Principado, sendo elas, em específico: Cleópatra (69 a.C. – 30 a.C.), Júlia Agripina Menor,
conhecida como Agripina Menor (15 d.C. – 59 d.C.), e Valéria Messalina (17/20 d. C. – 48 d.
C.). Optamos por essas figuras femininas históricas, não só por sua ampla presença em textos
poéticos e históricos, mas pelo que elas representavam para o sistema patriarcal romano, como
insígnia e símbolo. Trata-se, pois, de um esforço em tentar nos desfazer dos discursos
tendenciosos construídos a respeito delas, pelo menos no que tange sua hiper sexualização e
vilificação por atitudes que não eram de forma alguma incomum ou estranhas para aqueles
envolvidos em disputas por poder. Para esse fim, recorremos aos preceitos poéticos e aos
tratados de retórica, que, por sua natureza interdisciplinar e flexível, foram utilizados para as
representações dessas mulheres, seja no âmbito histórico ou poético. Com base no estudo e
análise desses tratados, e no estabelecimento de certos modelos de conduta (estereótipos)
previsto pelos preceitos poéticos, acreditamos que poderemos entender como esses retratos
foram intencionalmente construídos de forma vituperiosa, não somente por questões políticas
ou sociais, mas também por um segmento muito mais formal, inserido na própria educação
discursiva desses estudiosos.The aim of the present research is to study and analyze the portraits and representations of some
women in positions of power (or sovereignty) in Antiquity, especially during the Principate
period, namely: Cleopatra (69 BCE - 30 BCE), Julia Agrippina Minor, known as Agrippina
Minor (15 CE - 59 CE), and Valeria Messalina (17/20 CE - 48 CE). We have chosen these
historical female figures not only for their extensive presence in poetic and historical texts, but
also for what they represented within the Roman patriarchal system, as emblems and symbols.
It is therefore an effort to dismantle the biased discourses constructed about them, at least
concerning their hyper-sexualization and vilification for behaviors that were by no means
uncommon or strange for those involved in power struggles. For this purpose, we have turned
to poetic precepts and rhetorical treatises, which, due to their interdisciplinary and flexible
nature, were used for the representations of these women, whether in the historical or poetic
sphere. Based on the study and analysis of these treatises, and the establishment of certain
models of conduct (stereotypes) prescribed by poetic precepts, I believe we can understand how
these portraits were intentionally constructed in a vituperative manner, not only due to political
or social issues, but also as a result of a much more formal segment, embedded in the very
discursive education of these scholars
The challenge of reducing diesel consumption and greenhouse gas emissions : a perspective on the use of hydrogen in mining trucks.
No full textIn mining, the traditional system of operation relies on equipment that consumes large amounts of energy. In mine operations, trucks are widely used due to their flexibility, loading capacity, and adaptability to various terrain conditions. However, they have high diesel oil consumption and high emission rates of smoke, particulate matter, and mainly carbon gas from diesel engines. This article offers a comprehensive view on the effect of hydrogen added to the diesel engine in the search for renewable energy alternatives that are in tune with the reduction of the environmental impact arising from the use of petroleum-derived fuels. The article presents an overview about the challenges in reducing the diesel fuel consumption of trucks employed in mining. It approaches the effect of controlled hydrogen addition on diesel engine performance, consumption reduction, and greenhouse gas emissions. Followed by a discussion of the main technologies used to manufacture hydrogen and their production costs. The results of the studies show that hydrogen is a promising alternative for reducing operational, energy, and emissions costs, mainly carbon dioxide (CO2) and carbon monoxide (CO), but it faces barriers in production, storage, and supply costs. We highlight the “green hydrogen”, carbon-free, which contributes to the decarbonization process in mines, as open pit or underground ones
Housing market, oil prices, and macroeconomic volatility in the G7.
No full textIn this paper, we investigate house price shocks on the macroeconomic variables (financial market, inflation, and real sector) of the G7 economies. We use the GVAR to capture the spillover effects from the U.S. housing market and oil prices on these economies from 1991M3–2022M10. We identify the U.S. house price shock using the Structural Generalized Impulse Response Function, house supply and demand variables, and regional divergence. We find that the domestic stock markets and industrial production are the most sensitive to house price shocks. We further compare the importance of house and oil prices on domestic fluctuations. The estimates reinforce the previous findings: U.S. house prices are responsible for a quarter of the domestic volatility of the stock markets and industrial production. In the other macroeconomic segments, the effects of house prices are present, but in lower values. Our results show that house prices provoke more domestic fluctuations than oil prices. Finally, we also found that short and long‐term credit markets, as well as stock markets, transmit the house price shock to industrial production. Consequently, we provide potential channels to comprehend the spillover effect of U.S. house prices on international markets