A mean-field Babcock-Leighton solar dynamo model with long-term variability

Dynamo models relying on the Babcock-Leighton mechanism are successful in reproducing most of the solar magnetic field dynamical characteristics. However, considering that such models operate only above a lower magnetic field threshold, they do not provide an appropriate magnetic field regeneration process characterizing a self-sustainable dynamo. In this work we consider the existence of an additional \alpha-effect to the Babcock-Leighton scenario in a mean-field axisymmetric kinematic numerical model. Both poloidal field regeneration mechanisms are treated with two different strength-limiting factors. Apart from the solar anti-symmetric parity behavior, the main solar features are reproduced: cyclic polarity reversals, mid-latitudinal equatorward migration of strong toroidal field, poleward migration of polar surface radial fields, and the quadrature phase shift between both. Long-term variability of the solutions exhibits lengthy periods of minimum activity followed by posterior recovery, akin to the observed Maunder Minimum. Based on the analysis of the residual activity during periods of minimum activity, we suggest that these are caused by a predominance of the \alpha-effect over the Babcock-Leighton mechanism in regenerating the poloidal field.Comment: 21 pages, 6 figure

Political, general, or economic strikes? New types of strikes and workers’ contention in Italy (2008–2018)

The article provides an overview of workers’ collective actions in Italy between 2008 and 2018, which characterized a new wave of contention; the article focuses on the development of strike activities in this period. While the literature suggests an increase in general/political strikes and a decline of economic strikes, we argue that this distinction does not sufficiently account for the variety of strikes that has recently occurred. Our contribution aims to clarify the differences between three types of strikes: general political strike, general/large-scale economic strike, and local economic strike. The empirical analysis is based on a new data set of workers’ collective actions, including strikes, observed in Italy in the decade 2008–2018. The data set was built using protest event analysis (PEA). Multiple correspondence analysis (MCA) reveals three types of strikes that differ along these dimensions: the actors promoting them, the workers’ occupations involved, the issues claimed, the scale of action, and the addressee of the actions. Conclusions compare the characteristics of workers’ contentious actions between 2008 and 2018 with the old cycle of protests observable in the 1960s and 1970s, and suggest an integration of economic and political explanations to account for the new types of strikes

Political, General or Economic Strikes? New Types of Strikes and Workers' Contention

The article provides an overview of workers' collective actions occurred in Italy, characterizing a new wave of contention between 2008 and 2018. It focuses on the development of strike activities. While the literature suggests an increase in general/political strikes and a decline of economic strikes, we argue that this distinction does not sufficiently account for the variety of strikes that has recently occurred. Our contribution aims to clarify the differences between three types of strikes: general political strike, general/large-scale economic strike and local economic strike. The empirical analysis is based on a new dataset on workers' collective actions, including strikes, observed in Italy in the decade 2008-2018. The dataset was built using protest event analysis (PEA). Multiple correspondence analysis (MCA) allows us to show that the three types of strikes differ along the actors promoting them, the workers' occupations involved, the issues claimed, the scale of action and the target of the actions. Conclusions compare the characteristics of workers contention between 2008 and 2018 with the old cycle of protest and suggest to join economic and political explanations of strikes to account for the new types of strikes

O PROGRAMA SOCIAL E AMBIENTAL DOS IGARAPÉS DE MANAUS (PROSAMIM): A CONSTRUÇÃO DE UMA NOVA ESPACIALIDADE

Resumo Os processos de urbanização espelham, além de formas construídas e espaços produzidos, atores que vão configurando objetivamente a cidade. Manaus, com 2,0 mil de hab. enfrenta sérios problemas urbanos típicos das grandes cidades capitalistas, marcadas por um processo de crescimento urbano rápido e desordenado. Historicamente, a falta de alternativas habitacionais resultou na criação de assentamentos informais às margens dos igarapés, oferecendo riscos aos moradores dessas áreas. Neste contexto surge o PROSAMIM, com o objetivo de resolver os problemas sociais, urbanísticos e ambientais da cidade. Com foco neste programa entrevistamos trinta e três moradores (pesquisa qualitativa). Como resultado da pesquisa conhecemos as condições de vida e trabalho dos moradores e suas avaliações sobre o programa. Concluímos que eles estão satisfeitos com a atual moradia, apesar dos inúmeros problemas de infraestrutura e com as novas despesas de água e luz e sérios problemas de violência devido ao tráfico de drogas na área

Evidencias psicométricas del cuestionario de procrastinación académica en adolescentes estudiantes de una institución educativa del distrito de la Esperanza, 2021

La presente investigación tuvo la finalidad de determinar las evidencias psicométricas de la escala de procrastinación académica en estudiantes de una institución educativa del Distrito de Trujillo. El diseño empleado fue instrumental y la muestra quedó conformada por 350 alumnos de nivel secundario. La escala revisada fue la Escala de Procrastinación Académica EPA, creada por Busko (1998). Los resultados principales muestran que la estructura resultante fue de 2 factores y los índices de ajuste absoluto muestran valores de RMSEA=,08 y SRMR=,05. Asimismo, el ajuste comparativo muestra un CFI=,965 y TLI=,956. Con los resultados observados se concluye que presenta un buen ajuste del modelo. En lo que respecta a la confiabilidad, para la dimensión postergación de actividades se obtuvo un valor de ω=,86 y para la dimensión autorregulación académica un valor de ω=,90. Se concluye mencionando que el instrumento presenta adecuadas propiedades de medición que fundamenta su uso posterior en diferentes investigaciones

The Oral Tolerance as a Complex Network Phenomenon

Date of Acceptance: 23/05/2015 Funding: MSB acknowledges the Engineering and Physical Sciences Research Council (EPSRC) - UK grant EP/I032606/1. PJM and MD received regular scholarships from the Brazilian the following agency: Higher Education Personnel Training Coordination (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) CAPES http://www.fisica.uepg.br:7080/ppgfisica​/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

­­Atg9 interactions via its transmembrane domains are required for phagophore expansion during autophagy

During macroautophagy/autophagy, precursor cisterna known as phagophores expand and sequester portions of the cytoplasm and/or organelles, and subsequently close resulting in double-membrane transport vesicles called autophagosomes. Autophagosomes fuse with lysosomes/vacuoles to allow the degradation and recycling of their cargoes. We previously showed that sequential binding of yeast Atg2 and Atg18 to Atg9, the only conserved transmembrane protein in autophagy, at the extremities of the phagophore mediates the establishment of membrane contact sites between the phagophore and the endoplasmic reticulum. As the Atg2-Atg18 complex transfers lipids between adjacent membranes in vitro, it has been postulated that this activity and the scramblase activity of the trimers formed by Atg9 are required for the phagophore expansion. Here, we present evidence that Atg9 indeed promotes Atg2-Atg18 complex-mediated lipid transfer in vitro, although this is not the only requirement for its function in vivo. In particular, we show that Atg9 function is dramatically compromised by a F627A mutation within the conserved interface between the transmembrane domains of the Atg9 monomers. Although Atg9F627A self-interacts and binds to the Atg2-Atg18 complex, the F627A mutation blocks the phagophore expansion and thus autophagy progression. This phenotype is conserved because the corresponding human ATG9A mutant severely impairs autophagy as well. Importantly, Atg9F627A has identical scramblase activity in vitro like Atg9, and as with the wild-type protein enhances Atg2-Atg18-mediated lipid transfer. Collectively, our data reveal that interactions of Atg9 trimers via their transmembrane segments play a key role in phagophore expansion beyond Atg9ʹs role as a lipid scramblase.Abbreviations: BafA1: bafilomycin A1; Cvt: cytoplasm-to-vacuole targeting; Cryo-EM: cryo-electron microscopy; ER: endoplasmic reticulum; GFP: green fluorescent protein; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCS: membrane contact site; NBD-PE: N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine; PAS: phagophore assembly site; PE: phosphatidylethanolamine; prApe1: precursor Ape1; PtdIns3P: phosphatidylinositol-3-phosphate; SLB: supported lipid bilayer; SUV: small unilamellar vesicle; TMD: transmembrane domain; WT: wild type.</p

Curcumin, but not Prima-1, decreased tumor cell proliferation in the syngeneic murine orthotopic bladder tumor model

OBJECTIVE: Cigarette smoking is the main risk factor for bladder cancer development. Among the mediators of this effect of smoking is nuclear factor-kappa B. Curcumin suppresses cellular transformation by downregulating the activity of nuclear factor-kappa B. Prima-1 is a compound that induces apoptosis in human tumor cells, restoring the function of mutant p53. Our study aimed to evaluate the effects of curcumin and prima-1 in an animal model of bladder cancer. METHODS: Tumor implantation was achieved in six- to eight-week-old female C57BL/6 mice by introducing MB49 bladder cancer cells into the bladder. Intravesical treatment with curcumin and Prima-1 was performed on days 2, 6, 10, and 14. On day 15, the animals were sacrificed. Immunohistochemistry was used to determine the expression of cyclin D1, Cox-2, and p21. Cell proliferation was examined using PCNA. RESULTS: Animals treated with curcumin exhibited a higher degree of necrosis than animals in other groups. Immunohistochemistry showed reduced expression of cyclin D1 in the curcumin-treated group. All of the cells in mice treated with curcumin were p21 positive, suggesting that the p53 pathway is induced by this compound. Prima-1 did not induce any change in tumor size, necrosis, cell proliferation, or the expression of proteins related to the p53 pathway in this animal model. CONCLUSION: Curcumin showed activity in this animal bladder cancer model and probably acted via the regulation of nuclear factor-kappa B and p53. Therefore, curcumin is a good choice for the use in clinical trials to treat superficial bladder cancer as an alternative to bacillus Calmette-Guerin. In contrast, Prima-1 does not seem to have an effect on bladder cancer

ANÁLISE ECONÔMICA DA CITRICULTURA DE ROSÁRIO DO SUL/RS: UM ENFOQUE SOBRE A ADOÇÃO DE PROGRAMAS DE CERTIFICAÇÃO SOCIOAMBIENTAL

The fruit sector is one of the most important segments of agribusiness in Brazil. In addition to its high profitability and expressive use of hand labor, the fruit stands out as an important alternative to the increase in Brazilian exports of agricultural products. The new market demands reflect the adoption of certification seals that prove the quality and healthiness of the product, the consumer is assured of a safe food whose production respects the environment and the worker. In Rio Grande do Sul, the culture began to be implemented from the year 2000 when several municipalities in the region received funds from the federal government, especially the Rosary South, through the Program for Fruit of the southern half being a beneficiary of the company Citrusul. This article aims to analyze the characteristics of production and marketing of the company, in addition to identifying the possible benefits of a future adoption of environmental certification programs in the citrus industry in the municipality. This article builds on the literature review and as a way to obtain the information necessary to construct this study, we sought through interviews and case study. The study showed that adoption of certification seals would bring the opportunity to access markets more noble and demanding, since the company is already working to have fruit of excellent quality. However, due to the volume of its current production, it is believed that the high costs for registration need not bring a financial return for such an investment.http://dx.doi.org/10.5902/223611708803O setor frutícola é um dos mais importantes segmentos do agronegócio do Brasil. Além da sua elevada rentabilidade e expressiva utilização de mão-de-obra, a fruticultura destaca-se como uma importante alternativa para o aumento das exportações brasileiras de produtos agrícolas. As novas exigências do mercado refletem na adoção de selos de certificação que comprovam a qualidade e sanidade do produto, o consumidor tem a garantia de um alimento seguro, cuja produção respeita o meio ambiente e o trabalhador. No Rio Grande do Sul, a cultura começou a ser implantada a partir do ano de 2000 quando diversos municípios da região receberam recursos do governo federal, sobretudo, Rosário do Sul, através do Programa de Fruticultura da Metade Sul, sendo uma das beneficiárias a empresa Citrusul. Este artigo tem como objetivo analisar as características de produção e comercialização da empresa, além de identificar os possíveis benefícios de uma futura adoção de programas de certificações socioambientais no setor de citros do município. O estudo foi arquitetado a partir de uma revisão bibliográfica e através de entrevistas para obter informações primárias sobre o assunto. O trabalho mostrou que adoção de selos de certificação traria a oportunidade de acesso a mercados mais nobres e exigentes, uma vez que a empresa já trabalha para ter frutas de excelente qualidade. No entanto, devido ao volume de sua produção atual, acredita-se que os altos custos para seu registro não trazem retorno financeiro necessário para tal investimento