Fragmentation Experiment and Model for Falling Mercury Drops

The experiment consists of counting and measuring the size of the many fragments observed after the fall of a mercury drop on the floor. The size distribution follows a power-law for large enough fragments. We address the question of a possible crossover to a second, different power-law for small enough fragments. Two series of experiments were performed. The first uses a traditional film photographic camera, and the picture is later treated on a computer in order to count the fragments and classify them according to their sizes. The second uses a modern digital camera. The first approach has the advantage of a better resolution for small fragment sizes. The second, although with a poorer size resolution, is more reliable concerning the counting of all fragments up to its resolution limit. Both together clearly indicate the real existence of the quoted crossover. The model treats the system microscopically during the tiny time interval when the initial drop collides with the floor. The drop is modelled by a connected cluster of Ising spins pointing up (mercury) surrounded by Ising spins pointing down (air). The Ising coupling which tends to keep the spins segregated represents the surface tension. Initially the cluster carries an extra energy equally shared among all its spins, corresponding to the coherent kinetic energy due to the fall. Each spin which touches the floor loses its extra energy transformed into a thermal, incoherent energy represented by a temperature used then to follow the dynamics through Monte Carlo simulations. Whenever a small piece becomes disconnected from the big cluster, it is considered a fragment, and counted. The results also indicate the existence of the quoted crossover in the fragment-size distribution.Comment: 6 pages, 3 figure

Mitochondrial Oxidative Stress and Calcium-Dependent Permeability Transition are Key Players in the Mechanisms of Statins-Associated Side Effects

Statins are cholesterol-lowering medicines utilized worldwide and are associated with reduced risk of cardiovascular mortality and events. However, 0.5–10% of patients suffer from adverse effects especially on skeletal muscle. Recently, new onset of diabetes has been reported in subjects on statin therapy. Pro- and anti-oxidant effects of statins have been reported, thus fostering a debate. Previously reported data provide evidence that statins induce alterations in intracellular calcium homeostasis and mitochondrial dysfunctions that can be counteracted by antioxidants (e.g., CoQ10, creatine, and L-carnitine). Therefore, we have proposed that statin-induced inhibition of mitochondrial respiration leads to oxidative stress that opens a calcium-dependent permeability transition pore, an event that may lead to cell death. In addition, mitochondrial oxidative stress caused by statin treatment may be a signal for cellular antioxidant system responses such as catalase upregulation, possibly explaining the alleged statins’ antioxidant properties. Muscle mitochondrial dysfunction induced by statin treatment may be associated with the peripheral insulin resistance and may explain statins-induced new onset of diabetes. Together, the data presented in this review suggest that the statins’ detrimental effects can be prevented by co-administration of antioxidants

Cinco anos do PPGED-UEPA na Amazônia: trajetórias, avanços e possibilidades acadêmicas

Este artigo socializa a trajetória vivenciada pelo"Programa de Pós-Graduação em educação-Mestrado, do Centro de Ciências Sociais e Educação (CCSE), da Universidade do Estado do Pará"(UEPA), em seus cinco anos de existência. Apresenta os avanços e dificuldades apresentadas no"percurso de consolidação de seu projeto acadêmico, com base em levantamento bibliográfico e"documental. Com setenta dissertações defendidas"em duas linhas de pesquisa o PPGED tem contribuído para fortalecer a produção educacional em"contextos amazônicos. Mesmo com os avanços"significativos visualizados tanto na infraestrutura"como nos encaminhamentos didático-científicos,"o Programa sente falta de políticas institucionais"que garantam sua autonomia de gestão, o que inclui a destinação de orçamento necessário para"manter as suas ações. Neste aspecto, há necessidade de se manter diálogo permanente entre"o PPGED e as instâncias a que o programa está"vinculado, de modo a garantir condições para"produção do conhecimento e assim fortalecer o"campo educacional, especialmente na Amazônia Paraense."Palavras-chave: Educação. Programa de Pós- graduação. UEPA. Amazônia."Five years of "PPGED -UEPA in the Amazon: routes, trajectories, improvements and academic possibilities"This article socializes the trajectory experienced by the Post-graduate Program in Education (PPGED)Master’s Degree of Centro de Ciências Sociais e Educação (CCSE), of Universidade do Estado do Pará (UEPA), along its five years of existence. It presents improvements and difficulties emerged throughout the consolidation of its academic project, based on bibliographic and documental research. The PPGED has registered seventy seven developed dissertations in its two research areas and has contributed to strengthen the educational production within Amazonian contexts. Despite the relevant and evident progress achieved both in infrastructure and in scientific and didactic processes, the Program still lacks institutional policies that guarantee its management autonomy, which includes the destination of the necessary budget in order to maintain its actions. Concerning this, it is necessary to maintain permanent dialogue between PPGED and the other instances to which the program is linked, aiming at developing conditions for the production of knowledge and thus strengthening the educational field, especially in the Amazon of Para.Keywords: Education. Post Graduate Program. UEPA. Amazon." ""

LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering

[EN] Li2O-SiO2-ZrO2 (LZS) glass-ceramics have high mechanical strength, hardness, resistance to abrasion and chemical attack, but also a high coefficient of thermal expansion (CTE), which can be reduced adding alumina nanoparticles. The conventional glass-ceramic production is relatively complex and energy consuming, since it requires the melting of the raw materials to form a glass frit and a two-step milling process to obtain particle sizes adequate for compaction. This study describes the preparation of LZS glass-ceramics through a colloidal processing approach from mixtures of SiO2 and ZrO2 nanopowders and a Li precursor (lithium acetate obtained by reaction of the carbonate with acetic acid). Concentrated suspensions were freeze-dried to obtain homogeneous mixtures of powders that were pressed (100 MPa) and sintered conventionally and by spark plasma sintering. The effect of the alumina nanoparticles additions on suspensions rheology, sintering behavior and properties such as thermal expansion, thermal conductivity, hardness and Young's modulus were evaluated. (C) 2017 Elsevier Ltd. All rights reserved.This work has been supported by Ministerio de Economia y Competitividad (MINECO) and FEDER Funds under grant No MAT2016-67586-C3-R. Authors greatly acknowledge the financial Support of CAPES in the frame of the International Cooperation Program Science without Borders for Special Visiting Researcher PVE (MEC/MCTI/CAPES/CNPQ/FAPs/No 71/2013), Project no. A011/2013. A. Borrell acknowledges the MINECO for her Juan de la Cierva-Incorporacion contract (IJCI-2014-19839).Arcaro, S.; Novaes De Oliveira, A.; Gutierrez-Gonzalez, C.; Salvador Moya, MD.; Borrell Tomás, MA.; Moreno, R. (2017). LZS/Al2O3 nanostructured composites obtained by colloidal processing and spark plasma sintering. Journal of the European Ceramic Society. 37(16):5139-5148. https://doi.org/10.1016/j.jeurceramsoc.2017.03.023S51395148371

A quantum-like description of the planetary systems

The Titius-Bode law for planetary distances is reviewed. A model describing the basic features of this rule in the "quantum-like" language of a wave equation is proposed. Some considerations about the 't Hooft idea on the quantum behaviour of deterministic systems with dissipation are discussed.Comment: LaTex file, 17 pages, no figures. Version published in Foundations of Physics, August 200

Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems

A PL spherical harmonics-nodal collocation method is applied to the solution of the multidimensional neutron source transport equation. Vacuum boundary conditions are approximated by setting Marshak's conditions. The method is applied to several 1D, 2D and 3D problems with isotropic fixed source and with isotropic and anisotropic scattering. These problems are chosen to test this method in limit conditions, showing that in some cases a high order $P_L$ approximation is required to obtain accurate results and convergence. Results are also compared with the ones provided by several reference codes showing good agreement. It is also shown that Marshak's approximation to vacuum boundary conditions gives the same results that simulating vacuum with a purely absorbing medium and setting zero flux boundary conditions.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad under project ENE2011-22823, and the Generalitat Valenciana under project PROMETEO11/2014/008.Capilla Romá, MT.; Talavera Usano, CF.; Ginestar Peiro, D.; Verdú Martín, GJ. (2016). Nodal collocation method for the multidimensional PL equations applied to neutron transport source problems. Annals of Nuclear Energy. 87:89-100. https://doi.org/10.1016/j.anucene.2015.07.040S891008

Desempenho do inhame (taro) em plantio direto e no consórcio com crotalária, sob manejo orgânico.

Estudaram-se os efeitos do plantio direto em cobertura morta de aveia-preta e do consórcio com Crotalaria juncea, em sistema orgânico de produção de inhame, em ensaio na EE de Nova Friburgo(Pesagro-Rio), região serrana do estado do Rio de Janeiro. Utilizouse o delineamento de blocos ao acaso com quatro repetições, em esquema fatorial 2 x 2, onde os tratamentos corresponderam ao: modo de plantio (direto ou convencional) e modo de cultivo (monocultivo ou consórcio com crotalária). O cultivo consorciado com a leguminosa promoveu maior altura nas plantas do inhame, assim como reduziu a queima de folhas pelos raios solares. A população infestante de ervas espontâneas foi mais efetivamente controlada com a combinação entre consórcio e plantio direto. Nenhum dos tratamentos influenciou a produtividade do inhame, que foi considerada satisfatória, indicando o potencial do manejo orgânico adotado

TOIMINNANOHJAUSJÄRJESTELMÄN KÄYTTÖÖNOTON VAIKUTUS

Tässä tutkielmassa tutkitaan kuinka toiminnanohjausjärjestelmän käyttöönotto on vaikuttanut yrityksen tulokseen ja suorituskykyyn suomalaisissa yrityksissä 1999-2015. Tavoitteena on testata empiirisesti aiheuttaako toiminnanohjausjärjestelmän käyttöönotto merkittäviä säästöjä, yrityk-sen toiminnan tehokkuuden parannuksia ja muutoksia yrityksen kannattavuudessa. Toiminnanohjaus- eli ERP-järjestelmät integroivat yrityksen eri toimintoja esimerkiksi logistiikkaa, tuotantoa, kirjanpitoa, varastointia ja laskutusta yhteen järjestelmään ja näin ollen tehostavat yrityksen toimintaa useiden eri järjestelmien käytön sijaan. Onkin tärkeää selvittää kuinka toiminnanohjausjärjestelmien käyttöönotto on vaikuttanut yritysten kannattavuuteen ja voidaanko investointi nähdä tuottavana. Aikaisempien tutkimusten perusteella tulokset ovat ristiriitaisia; tutkimukset osoittavat, että vaikka ERP- järjestelmien käyttöönotto tutkitusti vaikuttaa ei-rahamääräisiin mittareihin, vaikutusta rahamääräisiin mittareihin ei aina pystytä todistamaan. Yritysten kannalta mielenkiintoista onkin ovatko kalliit ERP-järjestelmät, sekä niiden implementointiprosessit todella kannattavia investointeja. Tutkimuksen empiirisessä osiossa selvitettiin toiminnanohjausjärjestelmien käyttöönoton vaiku-tuksia suorituskykyyn suomalaisissa yhtiöissä, jotka ovat implementoineet toiminnanohjausjärjestelmän vuosina 1999-2015. Aineistona on käytetty julkisuudessa ilmoitettuja järjestelmähank-keita sekä tilinpäätöstietoja implementointiprosessin jälkeisiltä sekä edeltäviltä vuosilta. Suorituskyvyn muutosta on seurattu vertailemalla suorituskyvyn ja kannattavuuden muutosta implementoinnin jälkeen. Tutkimus on suoritettu määrällisenä tutkimuksena ja tilastollisina menetelminä on käytetty toistomittausten varianssianalyysiä sekä t-testiä parivertailulle. Tutkimuksessa havaittiin, että näyttäisi siltä, ettei toiminnanohjausjärjestelmien käyttöönotolla ei ole ollut vaikutusta kohdeyhtiöiden rahamääräiseen suorituskykyyn.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Balanço do nitrogênio e fósforo em solo com cultivo orgânico de hortaliças após a incorporação de biomassa de guandu.

Os objetivos deste trabalho foram avaliar os efeitos de faixas de guandu (Cajanus cajan) e da incorporação da biomassa proveniente de sua poda na fertilidade do solo e na produtividade de três hortaliças sob cultivo orgânico. O delineamento usado foi de blocos casualizados completos em esquema de parcelas subsubdivididas com três repetições. As produtividades de beterraba, cenoura e feijão-de-vagem não foram afetadas pelos tratamentos. Nas parcelas onde não houve incorporação da biomassa de guandu, o balanço de nitrogênio no sistema foi negativo, ao passo que com a incorporação, esse balanço foi positivo. Embora tenha ocorrido balanço positivo para o fósforo nas parcelas sem a incorporação de biomassa de guandu, houve um aumento significativo na absorção desse elemento pelas hortaliças quando o material foi incorporado. O sistema de cultivo em aléias de guandu pode representar uma prática vantajosa para os produtores orgânicos, por contribuir na manutenção da fertilidade do solo