The effect of a tangential frictional force on rotating disks: an experimental approach

This paper describes an experiment with two touching rotating disks, whose movement is followed by video analysis. Within the disks’ movements, there are intervals with sliding and intervals without sliding, that is, intervals with frictional forces between the touching surfaces and intervals without it. This system configuration allows for measurement of the changeable magnitudes and directions of frictional forces (much more difficult to set up with translational motion). This activity may be used to combat students misconceptions of “frictional force always opposes the motion” and “between the same two bodies, one gets the same frictional force,” commonly found in the classroom, or just to reinforce the rotational dynamics relationships

Diaqua­(6-bromo­picolinato-κ2 N,O)(nitrato-κ2 O,O)copper(II)

In the monomeric title complex, [Cu(C6H3BrNO2)(NO3)(H2O)2], the CuII ion is coordinated by a bidentate 6-bromo­picolinate ion, one nitrate ion and two water mol­ecules in a geometry inter­mediate between five- and six-coordinate. Conventional O—H⋯O hydrogen bonds link the complex mol­ecules, forming layers parallel to the ab plane

Plant breeding with marker-assisted selection in Brazil.

Over the past three decades, molecular marker studies reachedextraordinary advances, especially for sequencing and bioinformatics techniques.Marker-assisted selectionbecamepart of the breeding program routines of important seed companies, in order to accelerate and optimize the cultivar developing processes. Private seed companies increasingly use marker-assisted selection, especially for the species of great importance to the seed market, e.g. corn, soybean, cotton, and sunflower. In the Brazilian public institutions few breeding programs use it efficiently.The possible reasons are: lack of know-how, lack of appropriate laboratories, few validated markers, high cost, and lack of urgency in obtaining cultivars. In this article we analyze the use and the constraints of marker-assisted selection in plant breeding programs of Brazilian public institute

Shoreline Dynamics in arch Caparica-Espichel: Fonte da Telha case study

Este estudo pretende avaliar a dinâmica da linha de costa no arco Caparica-Espichel, nos últimos 40 anos. Esta avaliação baseia-se na análise de fotografias aéreas e ortofotomapas das décadas de 1960, 1980, 1990 e de 2000. Incluem-se: (i) a avaliação de incertezas associadas à definição, georreferenciação e interpretação de imagens aéreas; (ii) a escolha dos indicadores de linha de costa; e (iii) a determinação do balanço erosão/acumulação. São apresentados os balanços e as taxas de variação de posicionamento da linha de costa ao longo do arco Caparica-Espichel, entre 1967-2008. Inclui-se uma classificação por setores litorais, tendo sido distinguidos 9, com comportamentos tendencialmente erosivos, com acreção e de estabilidade dinâmica. Os maiores valores de erosão foram registados entre a Nova Praia e a Praia da Riviera. A acreção registou-se junto à praia do Castelo e a norte da Lagoa de Albufeira. Entre estes setores observou-se uma transição gradual norte-sul de valores positivos para valores negativos na tendência evolutiva da linha de costa. No caso da Fonte da Telha, pode distinguir-se um comportamento contrastado entre o setor norte com valores de dinâmica da linha de costa positivos e o setor sul com valores negativos. Estespossuem uma forte relação com a pressão antrópica, especialmente em época balnear e sobre as dunas, que neste setor se traduz na instalação de apoios de praia, parques de estacionamento, pisoteio e caminhos desordenados.This study aims to assess the dynamics of the shoreline in Caparica-Espichel of the last 40 years, based on aerial imagery analysis of the 1960, 1980, 1990 and 2000 decades. The approach is based on: (i) the evaluation of uncertainties associated with the setting, georeferencing and interpretation of aerial images; (ii) the choice of shoreline indicators; and (iii) the erosion/accumulation budget. The shoreline rates and time variable trend are also an issue. A coastal classification based on erosive and accumulative tendencies is included. The largest erosion values were recorded between New Beach and Riviera Beach. The accretion recorded on the beachfront of the Castle and north of the Lagoa de Albufeira. A gradual north-south transition of the shoreline evolutionary trend was observed between these sectors: from positive to negative values. Finally, we present the Fonte da Telha case study, describing the local relationship between the erosion/accumulation balance and land use. In the case of Fonte da Telha, it can be distinguished a mixed behaviour between the northern sector with positive shoreline dynamic values and the southern sector with negative values. These have a strong relationship with the human pressure, especially in summer season and over the dunes, reflecting the installation of beach facilities, car parks, trampling and wayward ways.info:eu-repo/semantics/publishedVersio

Tamanho do genoma em coqueiro (Cocos nucifera L.) via citometria de Fluxo.

O objetivo do presente trabalho foi determinar o tamanho do genoma do coqueiro (Cocos nucífera L.) via determinação do conteúdo de DNA estimado via citometria de fluxo. Quatorze genótipos de coco, seis do tipo anão e oito do tipo gigante, foram utilizados nesse estudo. Para tal, amostras de folíolos medindo aproximadamente 0,5 cm2, por genótipo foram maceradas em solução tampão e filtradas para obtenção de uma suspensão dos núcleos. Posteriormente, os núcleos foram coloridos com iodeto de propídeo e em seguida foi adicionado RNase em cada amostra. Como padrão interno foi utilizado a cultivar CE-777 de milho (Zea mays L.). Após 30 minutos, as amostras foram analisadas em citômetro de fluxo (Partec PA II); para cada genótipo foi feito a leitura de cinco amostras. O conteúdo 2C de DNA de cada genótipo foi determinado, com médias variando de 2,74 pg a 2,86 pg, sendo a média geral 2,80 pg o que corresponde a 2.744 Mpb. O conteúdo de DNA do grupo Gigante foi o mais varável sendo o maior conteúdo estimado para o Gigante de Rennel, e o menor conteúdo para Gigante do Oeste Africano; o grupo Anão teve uma menor variação. A média do conteúdo 2C de DNA do grupo gigante foi de 2,80 pg e a do grupo Anão foi de 2,78pg. Os coeficientes de variação variaram de 2,5% a 3,1%, o que indica a precisão das medições. O teste Scott e Knott a 5% de probabilidade, agrupou os genótipos em 4 classes de acordo com as médias do conteúdo de DNA. Os resultados permitiram concluir que a espécie apresenta baixo conteúdo de DNA quando comparada com outros membros da família Arecaceae

Land use changes in the Douro Valley and carbon emissions

Deforestation for economic development and urbanisation or urban sprawl as a result of human population growth is a common feature of land-use change and is an important source of increased atmospheric CO2. At the global level, carbon emissions from burning fossil fuels are two to three times higher than carbon sequestration by land systems, mainly forests and woody vegetation. The work presented herein focuses on the identification of carbon balance shifts due to land use changes in a group of municipalities located in the Douro River Valley in northern Portugal, where the dominance of vineyards and forestry uses over urban occupation is the norm. However, when urban sprawl occurs through the replacement of forested areas by urban uses, the ability to sequester carbon dioxide is reduced while its production rates increase. A thorough study (Lourenço et al., 2008) of land uses evolution between 1990 and 2000 shows that urban uses have been growing near Vila Real as well as vineyard plantations. Forest fires and a complex topography are major causes for the growth of abandonment, which make these areas more prone to erosion and desertification.Portuguese Foundation for Science and Technology in the scope of the research project PTDC/ECM/73069/200

Dilated fetal bowel as indication for prenatal diagnosis of cystic fibrosis

Dilated fetal bowel is a sonographic fi nding that is associated to meconium ileus, a feature of cystic fi brosis (CF). Prenatal diagnosis of CF is possible through analysis of the cystic fi brosis transmembrane regulator gene mutations. A male infant is described, who was referred to our Prenatal Diagnosis Center a 17th week of gestation with a dilated bowel loop on a prenatal scan. Amniocentesis was performed at 23rd week gestation and a homozygous F508del mutation was found. He was born at 38 weeks gestation, after an otherwise unremarkable pregnancy, and admitted to Neonatal Intensive Care Unit. He showed progressive abdominal distension without stools and was transferred to another Hospital to surgery. A total occlusion of terminal ileum with meconium and a microcolon were found, and resection of 8 cm of ileum and an ileostomy were performed. The characteristic sonographic fi nding of a dilated bowel is an indication to search for CF mutations

Bis(triphenyl­guanidinium) tetra­chlorido­cuprate(II)

The structure of the title compound, (C19H18N3)2[CuCl4], consists of square-planar [CuCl4]2− anions and triphenyl­guanidinium cations. The CuII ion occupies a crystallographic inversion centre. In the cation, the dihedral angles between the phenyl rings and the plane defined by the central guanidinium fragment are in the range 51.9 (4)–64.4 (3)°. N—H⋯Cl hydrogen bonds assemble the ions into infinite chains running along the b axis

Colon cancer chemoprevention by sage tea drinking: decreased DNA damage and cell proliferation

Salvia officinalis and some of its isolated compounds have been found to be preventive of DNA damage and increased proliferation in vitro in colon cells. In the present study, we used the azoxymethane model to test effects of S. officinalis on colon cancer prevention in vivo. The results showed that sage treatment reduced the number of ACF formed only if administered before azoxymethane injection, demonstrating that sage tea drinking has a chemopreventive effect on colorectal cancer. A decrease in the proliferation marker Ki67 and in H2O2-induced and azoxymethane-induced DNA damage to colonocytes and lymphocytes were found with sage treatment. This confirms in vivo the chemopreventive effects of S. officinalis. Taken together, our results show that sage treatment prevented initiation phases of colon carcinogenesis, an effect due, at least in part, to DNA protection, and reduced proliferation rates of colon epithelial cell that prevent mutations and their fixation through cell replication. These chemopreventive effects of S. officinalis on colon cancer add to the many health benefits attributed to sage and encourage its consumption.Fundação para a Ciência e a Tecnologia (FCT) - grant SFRH/BD/35672/2007, SFRH/BD/64817/200

In-situ and laboratory airtightness tests of structural insulated panels (SIPs) assemblies

One of the main factors influencing building airtightness is the construction typology. As building environmental performance requirements raise so does the prevalence of less conventional envelope construction systems as modular structural insulated panels (SIPs) buildings. In this paper, the airtightness performance of a constructive solution based on SIPs was evaluated. Airtightness tests were performed on the laboratory according to the EN 12114-2000 methodology. One complete exterior wall assembly and another one with the inclusion of a window were tested to determine their performance as an effective air barrier. The impact of the window framing in the overall resistance to air leakage was also determined. Additionally, the airtightness of a dwelling using these SIPs was measured during the construction phase and after commissioning. The objective was not only the assessment of the ACH50 difference between the two stages, but also the comparison with  previously tested conventional envelopes on the same climate. Laboratory and field test data resulted in mismatching values. Workmanship and unforeseen leakage paths were found to be the main contributors to these findings. Moreover, the case study displayed a superior airtightness performance when compared to heavy type construction solutions, common amongst the Portuguese building stock. Additional work is needed to identify and quantify envelope airpaths in order to properly design lightweight buildings solutions. FCT-Fundação para a Ciência e a Tecnologia, the funding of the Doctoral Grant PD/BD/135162/2017, through the Doctoral Programme EcoCoRe. This paper is a result of the project “H0ME ZERO”, with the reference POCI -01-0247-FEDER-017840, co-funded by the European Regional Development Fund (ERDF), through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under the PORTUGAL 2020 Partnership Agreement HOME This work was financially supported by : Project POCI-01-0145-FEDER-007457 -CONSTRUCT -Institute of R&D In Structures and Construction funded by FEDER funds through COMPETE 2020 -Programa Operacional Competitividade e Internacionalização POCI – and by national funds through - Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio