1,156 research outputs found
Water crisis in Parana: Causes and consequences
The water crisis that Paraná is going through is unprecedented in the last 90 years. Therefore, the objective of this work is to present the problem caused by it, mainly at the Paraná State, in which it has worsened since 2019. The El Niño and La Niña phenomena have relevant role in the temporal distribution anomalies of rainfall, causing, respectively, increase or decrease in precipitation in periods of marked variation in the average temperature of the Pacific Ocean. The scarcity of rain corroborates several sectors of society. According to Department of Rural Economy (in Portuguese: Departamento de Economia Rural – DERAL), the losses computed for soybeans represent more than R 2.2 billion and for beans, the losses exceed R$ 395 million. All this amount will stop circulating in the Paraná economy, affecting practically all segments. The measures that must be adopted by Paraná Sanitation Company (in Portuguese: Companhia de Saneamento do Paraná – SANEPAR), together with public policies, must not be only emergency and immediate, it must be planned and implemented with a view to the long term
Effect of the thermal modification and nano-ZnO impregnation on the deterioration of Caribbean pine wood
This study aimed to investigate the effect of thermal modification and nano-zinc oxide (nano-ZnO) particle impregnation on the deterioration of Caribbean pine wood under field conditions. Samples were thermally-modified at various temperature levels (control, 180 °C, 200 °C, and 220 °C). Nano-ZnO impregnation was done with an aqueous solution at 1,5 % in an autoclave under two-steps of pressure and vacuum. Unmodified and thermally-modified, non-impregnated and nano-ZnO-impregnated samples were exposed to deterioration for five months in field tests. A deterioration index was used to evaluate the health condition of the samples. The mass loss and occurrence of termite tunnels in percentage were also determined. The nano-ZnO impregnation improved the resistance of unmodified wood to field-deterioration. The thermal modification at 180oC and 200ºC increased the wood deterioration and nano-ZnO impregnation did not improve their resistance. Unmodified and 220 ºC-modified samples had lower mass loss by xylophages than other thermal treatments regardless of the nanoparticle impregnation. The nano-ZnO impregnation decreases the occurrence of termite tunnels in unmodified, 200 ºC and 220 ºC-modified samples
Spectral ordering and 2-switch transformations
We address the problem of ordering trees with the same degree sequence by their spectral radii. To achieve that, we consider 2-switch transformations which preserve the degree sequence and establish when the index decreases. Our main contribution is to determine a total ordering of a particular family by their indices according to a given parameter related to sizes in the tree
Towards Understanding Political Interactions on Instagram
Online Social Networks (OSNs) allow personalities and companies to
communicate directly with the public, bypassing filters of traditional medias.
As people rely on OSNs to stay up-to-date, the political debate has moved
online too. We witness the sudden explosion of harsh political debates and the
dissemination of rumours in OSNs. Identifying such behaviour requires a deep
understanding on how people interact via OSNs during political debates. We
present a preliminary study of interactions in a popular OSN, namely Instagram.
We take Italy as a case study in the period before the 2019 European Elections.
We observe the activity of top Italian Instagram profiles in different
categories: politics, music, sport and show. We record their posts for more
than two months, tracking "likes" and comments from users. Results suggest that
profiles of politicians attract markedly different interactions than other
categories. People tend to comment more, with longer comments, debating for
longer time, with a large number of replies, most of which are not explicitly
solicited. Moreover, comments tend to come from a small group of very active
users. Finally, we witness substantial differences when comparing profiles of
different parties.Comment: 5 pages, 8 figure
On the spectral characterization of the p-sun and the (p,q)-double sun L. Emilio Allem, Lucas G.M. da Silveira e Vilmar Trevisan
In 1973 Schwenk [7] proved that almost every tree has a cospectral mate. Inspired by Schwenk's result, in this paper we study the spectrum of two families of trees. The p-sun of order is a star with an edge attached to each pendant vertex, which we show to be determined by its spectrum among connected graphs. The -double sun of order is the union of a p-sun and a q-sun by adding an edge between their central vertices. We determine when the -double sun has a cospectral mate and when it is determined by its spectrum among connected graphs. Our method is based on the fact that these trees have few distinct eigenvalues and we are able to take advantage of their nullity to shorten the list of candidates
Technological innovations in the work environment and the career of the millennium generation
Purpose – The purpose of this paper is to identify the relationship of career anchors with three aspects: themillennials’ professional skills, the millennials’ awareness of the replacement of jobs with new technologiesand the technological stress in the millennials’ working environment.Design/methodology/approach – The responses of 200 questionnaires were analyzed using descriptiveand variance analysis techniques.Findings – Among the three hypotheses raised, two were confirmed, showing that these young peoplerecognize the development of professional skills through new technologies, but are not highly sensitive to thestress associated with technological innovations.Originality/value – The paper contributes to a recent debate, which emphasizes the impact of theapplication of new technologies on the nature of study and employment levels
Conservação e manutenção de espécies nativas do gênero Paspalum no Bioma Pampa
O bioma Pampa é um ecossistema único, caracterizado por extensos campos, marcado por uma diversidade de formações vegetais e pela rica biodiversidade adaptada a condições climáticas variadas, com invernos rigorosos e verões quentes. Além de servir como base para a produção pecuária, o bioma contribui com uma série de serviços ecossistêmicos como regulação hídrica, polinização e captura de carbono, e tem um papel importante na identidade regional e prática cultural. No entanto, enfrenta desafios como a fragmentação do habitat e a perda da vegetação natural com a conversão das áreas de pastagem para agricultura, silvicultura ou até mesmo má utilização no manejo da pecuária. As gramíneas nativas do gênero Paspalum se destacam no bioma pela quantidade e por apresentarem bom valor forrageiro. Assim, o objetivo deste trabalho oi abordar aspectos da conservação das espécies do gênero Paspalum, conservação do germoplasma, o melhoramento genético, a utilização da hibridação artificial no melhoramento genético de Paspalum spp. e o lançamento de novas cultivares de Paspalum notatum.Os recentes estudos que analisaram características de importância para o melhoramento das plantas, bem como as características agronômicas das espécies do gênero, têm demonstrado um potencial promissor, apresentando bons valores de herdabilidade e variabilidade genética e produções de forragem que ultrapassam cultivares já existentes, conclusões estas que encorajam os melhoristas a darem continuidade nos programas de melhoramento genético do gênero.The Pampa biome is a unique ecosystem characterized by extensive grasslands, marked by a diversity of vegetation formations and rich biodiversity adapted to varying climatic conditions, with harsh winters and hot summers. Besides serving as the basis for livestock production, the biome provides a range of ecosystem services such as water regulation, pollination, and carbon sequestration, and plays an important role in regional identity and cultural practices. However, it faces challenges such as habitat fragmentation and the loss of natural vegetation due to the conversion of pasture areas for agriculture, forestry, or improper livestock management. Native grasses of the genus Paspalum stand out in the biome due to their abundance and good forage value. Therefore, the objective of this work was to address aspects of Paspalum species conservation, germplasm conservation, genetic improvement, the use of artificial hybridization in Paspalum spp. genetic improvement, and the release of new cultivars of Paspalum notatum.Recent studies that have analyzed characteristics important for plant improvement, as well as the agronomic traits of species within the genus, have shown promising potential, with good values of heritability and genetic variability, and forage yields surpassing existing cultivars. These conclusions encourage breeders to continue with genetic improvement programs for the genus
Mal de arquivo – Um desafio para a filosofia da educação?
A partir da reflexão extraída do livro “Mal de arquivo: uma impressãofreudiana”, de Jaques Derrida, o artigo pretende investigar as consequênciasda metáfora de “mal de arquivo” para o campo da filosofia da educação. Porintermédio da crença de que a tradição do reprimido se inscreve na ideia dearquivo, procura potencializar o termo para interpretar alguns problemasexistentes no campo da relação entre filosofia e educação. Especialmente,dirige o olhar para a forma como surge o discurso da filosofia, bem como adinâmica cultural que persiste em seguir certas orientações, sua autoridadee a sua genealogia bastante presente no âmbito acadêmico contemporâneo.A desconstrução da metafísica se soma ao trabalho da psicanálise, fazendoo proibido aflorar à consciência, e, portanto, ao nível literal da escritura.E assim, o acontecimento da compreensão pode auxiliar a desmobilizar acompulsão à repetição que se instaurou no arquiv
Produtividade de morangueiro sob diferentes níveis de adubação química em pré-plantio.
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Prognose de crescimento volumétrico individual de árvores de Eucalyptus, em povoamentos na Região Centro Sul.
A prognose do crescimento volumétrico individual foi realizada com dados de um ensaio de adubação de Eucalyptus dunnii e de competição de espécies incluindo E. bicostata, E. “cambiju” (híbrido natural), E. deanei e E. viminalis, implantados em Vila Velha, Ponta Grossa, Paraná. Utilizou-se para este estudo o método das regressões sucessivas modificado para a forma exponencial, incluindo como constante o volume aos três anos de idade. Os coeficientes de correlação obtidos, os erros padrão das estimativas e a distribuição de resíduos, para os modelos propostos no presente estudo, demonstraram a possibilidade do uso do método das regressões sucessivas, modificado para a forma exponencial, com a inclusão do volume na idade base de três anos, e a expectativa de sobrevivência ao longo da rotação, para a prognose de volumes individuais de árvores de espécies de Eucalyptus. A precisão da prognose é alta para espécies bem adaptadas, que apresentem sobrevivência elevada, até o final da rotação por exemplo E.deanei e E. dunnii. O E. “cambiju” apresentou acentuado decréscimo de sobrevivência ao longo da rotação. Neste caso, para maior precisão, foi necessário a inclusão no modelo do valor da recíproca da sobrevivência. Populações com baixo potencial de crescimento, apresentam volumes individuais e populacionais baixos, mesmo com alta sobrevivência. O E. viminalis e o E. cambiju, ambos com baixa sobrevivência ao final da rotação, apresentaram volumes individuais mais elevados que as outras espécies, em idades mais elevadas, exceto E. dunnii
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