4,505 research outputs found
Soil phosphorus properties and management for perennial crops in the central Amazon.
Predominant soils in the Brazilian Amazon. Phosphorus constraints to continuous soil use in the Brazilian Amazon. Phosphorus fertilization to perennial crops in the central Amazon. Phosphorus budgets in perennial crop plantations
Wine production with immobilized yeasts on grape pomace
The alcoholic fermentation is one of the most important stages in the winemaking process
and contributes decisively for the quality of the final product, particularly aromatic
characteristics. The immobilization of yeast cells in fermentation processes presents several
technological and economic advantages when compared with free cells systems, such as
increased productivity and greater tolerance of the cells to inhibitory substances.
In this context, the objective of this work consisted in using immobilized yeasts for driving
and controlling the alcoholic fermentation process in winemaking. The immobilization of
Saccharomyces cerevisiae took place on grape pomace by natural adsorption. The evolution
of the alcoholic fermentation was followed daily by measuring must density until a value
lower than 1000 kg/m3
was reached. Physical-chemical and sensorial characterization of the
wines, produced with free and immobilized cells, were carried out.
The immobilized yeasts were able to effectively conduct the alcoholic fermentation and
therefore, to produce wine. Sensory analysis demonstrated the existence of perceptible
olfactory differences in wines produced by free cells and immobilized cells. Moreover, the
produced wines presented significant differences respecting color attributes.A fermentação alcoólica é uma das etapas mais importantes no processo de produção de
vinho e contribui decisivamente para a qualidade final do produto, particularmente o aroma.
A imobilização de células de levedura em processos fermentativos apresenta diversas
vantagens tecnológicas e económicas quando comparada com sistemas de células livres, tais
como incremento da produtividade e maior tolerância das células a substâncias inibitórias.
Neste contexto, o objectivo do trabalho consistiu na utilização de leveduras imobilizadas para
para a condução e controlo do processo de fermentação alcoólica em vinificação. A
imobilização de Saccharomyces cerevisiae foi realizada por adsorção natural num suporte
natural constituído por bagaço de uva. A evolução da fermentação foi seguida diariamente
pela medição da massa volúmica, sendo dada por terminada para valores inferiores a 1000
kg/m3
. Os vinhos produzidos, quer com células livres quer com células imobilizadas, foram
avaliados por caracterização físico-química e por análise sensorial.
As leveduras imobilizadas foram capazes de conduzir eficazmente as fermentações alcoólicas
e, por conseguinte, de produzir vinho. A análise sensorial dos vinhos demonstrou a
existência de diferenças olfactivas perceptíveis nos vinhos produzidos a partir de células livres e de células imobilizadas. Além disso, as análises de cor demonstraram que os vinhos
produzidos apresentaram diferenças significativas
Improving light harvesting in polymer photodetector devices through nanoindented metal mask films
To enhance light harvesting in organic photovoltaic devices, we propose the incorporation of a metal (aluminum) mask film in the system’s usual layout. We fabricate devices in a sandwich geometry, where the mask (nanoindented with a periodic array of holes of sizes d and spacing s) is added between the transparent electrode and the active layer formed by a blend of the semiconducting polymer P3HT and substituted fullerene. Its function is to promote trapping of the incident light into the device’s cavity (the region corresponding to the active layer). For d, we set a value that allows light diffraction through the holes in the relevant absorption range of the polymer. To optimize the mask structure, we consider a very simple model to determine the s leading to trapped fields that are relatively intense and homogeneous within the device. From measurements of the action spectra, we show that, indeed, such architecture can considerably improve the resulting photocurrent efficiencies—one order of magnitude in the best situation studied.
Fabrication and Electrical Characterization of Translucent Bi 12
The production of high-density Bi12TiO20 ceramics, their transmission spectrum, and impedance features are reported. The samples were synthesized at 700°C/6 h and sintered at 800°C/3 h. This procedure yielded translucent ceramics with relative density of 99.2±0.5% and average grain size of 3.1±1.6 μm. Samples with 0.5 mm thickness were translucent with optical transmission of about 30% at 800 nm. The electrical and dielectric properties of the high-density ceramics were studied and compared with those measured for samples with lower density and also with the literature about Bi12TiO20 single crystals. The activation energy for the conduction process in high-density ceramic was 0.99 eV, and the dielectric permittivity was 40 at 200°C. These values are comparable to those reported for single crystals
Aspectos funcionais e nutricionais do tomate: uso de agrotóxicos na tomaticultura de São José de Ubá (RJ).
bitstream/item/108098/1/2008-DOC-0095.pd
Solo: um patrimônio ameaçado.
bitstream/item/26700/1/Solo-um-patrimnio-ameaado-Portal-Dia-de-Campo.pd
Aspectos teórico-metodológicos da abordagem participativa na agricultura familiar.
bitstream/item/24820/1/doc121-2010-agricultura-familiar.pd
Trends from the last decade
Publisher Copyright: © 2022 Sociedade Portuguesa de PneumologiaIntroduction and objectives: Nontuberculous mycobacteria (NTM) are opportunistic human pathogens found in the environment. The transmission seems to be associated with inhalation of aerosol droplets, ingestion or trauma events. Recent studies indicate that NTM disease is increasing worldwide, however, the true clinical impact of NTM infections is difficult to determine due to challenges in discriminating between disease and colonization as they are ubiquitous in the environment. In addition, understanding the epidemiology of NTM is difficult and has not yet been established. In this work, we used a country NTM representative collection from the National Reference Laboratory for Tuberculosis (NRL-TB) of the National Institute of Health (INSA), to characterize the circulation trends of NTM species in Portugal and the most affected regions, contributing to a better understanding of the NTM epidemiology. Material and methods: We conducted a nationwide retrospective study where all individuals with positive NTM cultures at the NRL-TB of the INSA from 2014 to December 2020 were included. Positive cultures were identified using GenoType Mycobacterium CM/AS® (Hain Lifescience) according to manufacturer's instructions, or hsp65 DNA sequencing as previously described. Social-demographic data from patients were also analyzed and patients classified into 3 groups according only to microbiological data, “definite NTM disease”, “NTM colonization” and, “possible NTM disease”. Results: In the period 2014-2020, the NRL-TB performed 50397 cultures. Among these, 1118 cultures were NTM positive retrieved from 944. Most of our cases were in patients whose mean age was 64±15.9 years, and no significant differences between gender was observed, although more frequent in male patients. Overall, from the 944 cases, we were able to identified 93 “definite NTM disease” cases and 79 “possible NTM disease”. Mycobacterium avium complex (MAC) (40,8%), Mycobacterium abscessus-chelonae complex (MABC) (9,6%) and Mycobacterium fortuitum (6,3%) were responsible for most of the infections. The geographical distribution of NTM cases varied significantly and was possible to observe that was independent of population density. The region were most cases occurred was Lisbon Metropolitan Area (31,9%), followed by North (25,3%) and Centre (24,4%), however North region has the highest number of “definite NTM disease” cases (n=33). Conclusions: This is the first national wide epidemiological study on this subject, contributing to a better understanding of NTM dynamics in Portugal. MAC was the NTM species responsible for the majority of infections and, LMA the region with the highest number of cases. It was also possible to conclude that the number of NTM isolates is independent of the demography of the region.publishersversionpublishe
Immigration Enforcement and Fairness to Would-Be Immigrants
This chapter argues that governments have a duty to take reasonably effective and humane steps to minimize the occurrence of unauthorized migration and stay. While the effects of unauthorized migration on a country’s citizens and institutions have been vigorously debated, the literature has largely ignored duties of fairness to would-be immigrants. It is argued here that failing to take reasonable steps to prevent unauthorized migration and stay is deeply unfair to would-be immigrants who are not in a position to bypass visa regulations. Importantly, the argument here is orthogonal to the debate as to how much and what kinds of immigration ought to be allowed
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