3,572 research outputs found

    Análise de imagens no estudo morfológico e fisiológico de sementes de abóbora.

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    A obtenção de sementes de abóbora com alta qualidade fisiológica é fundamental para colocar a produção nacional em condições de competitividade com as sementes importadas. Uma técnica que vem sendo utilizada recentemente para estudos relacionados à elucidação de vários aspectos do comportamento das sementes é a análise de imagens, incluindo as obtidas por meio do raio X. Esta técnica consiste em radiografar sementes com o objetivo de avaliar a morfologia interna e, assim, estabelecer relações com o desempenho da semente. O objetivo do presente estudo foi verificar se a técnica de raio X pode ser utilizada com sucesso na detecção de anormalidades e seus reflexos na qualidade fisiológica de sementes de abóbora. Foram utilizadas sementes de abóbora 'Brasileirinha' provenientes de frutos com diferentes estádios de maturação (30, 40, 50 e 60 dias após a antese). Em cada época, as sementes foram extraídas imediatamente após a colheita ou após o armazenamento dos frutos por 15 dias. No teste de raio X as sementes foram submetidas à intensidade de 25 kV por 40 segundos e, em seguida, foi conduzido teste de germinação sob temperatura alternada de 20-30ºC. Após quatro dias foi realizada a primeira contagem e após oito dias a última leitura, computando-se as porcentagens de plântulas normais, anormais e as sementes mortas. Após a obtenção do resultado do teste de germinação foi feita comparação desses resultados com imagens da morfologia interna de cada semente, obtidas por meio do raio X. Foi constatado que a técnica de raio X é eficiente na detecção de sementes mal formadas bem como de sementes vazias de abóbora e estas afetam negativamente sua germinação

    Aqua­(4,4′-bipyridine-κN)bis­(1,4-dioxo-1,4-dihydronaphthalen-2-olato-κ2 O 1,O 2)zinc 4,4′-bipyridine mono­solvate dihydrate

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    The reaction of 2-hy­droxy-1,4-naphtho­quinone and 4,4′-bipyridine with zinc acetate produced the title compound, [Zn(C10H5O3)2(C10H8N2)(H2O)]·C10H8N2·2H2O. The bond lengths and angles around the metal atom indicate a deviation from octa­hedral geometry. The two naphtho­quinone ligands coordinate in a cis fashion, with the 4,4′-bipyridine ligand and the water mol­ecules completing the coordination sphere of the metal atom. The asymmetric unit contains also one free 4,4′-bipyridine mol­ecule and two uncoordinated water mol­ecules. These mol­ecules make contacts with the complex through O—H⋯N and O—H⋯O hydrogen bonds, creating a layer two-dimensional network parallel to (121)

    Study of vital sign monitoring with textile sensors in swimming pool environment

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    This paper presents the results of a series of experiments aiming at the optimisation of vital sign monitoring using textile electrodes to be used in a swimsuit. The swimsuit will integrate sensors for the measurement of several physiological and biomechanical signals; this paper will focus on ECG and respiratory movement analysis. The data obtained is mainly intended to provide tools for evaluation of high-performance swimmers, although applications can be derived for leisure sports and other situations. A comparison between electrodes based on different materials and structures, behaviour in dry and wet environments, as well as the behavior in different extension states, will be presented. The influence of movement on the signal quality, both by the muscular electrical signals as well as by the displacement of the electrodes, will be discussed. The final objective is the integration of the electrodes in the swimsuit by knitting them directly in the suit’s fabric in a seamless knitting machineFundação para a Ciência e a Tecnologia (FCT) - PTDC/EEAELC/70803/200

    Identification of hazardous nanoparticles present in the Caribbean Sea for the allocation of future preservation projects

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    The deposition of remaining nanoparticles in the Caribbean Sea generates the formation of potentially dangerous elements, which influence at the imbalance of ecosystems. The detection of nanoparticles is not simple and the use of conventional methods is difficult application, which is why we highlight the immediacy and importance of this research for the areas of marine biology, urbanism, engineering and geosciences, applied in the Caribbean Sea. The general objective of this study is to evaluate the use of advanced methods for the determination of toxic nanoparticles, which can directly affect the development of marine organisms in the aquatic ecosystem in waters of the Caribbean Sea, favoring the construction of future international public policies with the elaboration of projects capable of mitigating these levels of contamination. The morphology and structure of nanoparticles were analyzed by emission scanning electron microscope with a high-resolution electron microscope. The nanoparticles smaller than 97 nm were identified in different proportions. The morphological analyses indicated nanoparticles' presence in the form of nanotubes, nanospheres, and nanofibers, which were shown in an agglomerated form. The presence of potentially hazardous elements, such as As, Cd, Pb, Mg, Ni and V were verified. In addition, the presence of asbestos in the form of minerals was confirmed, and that of titanium dioxide was found in large quantities. The results provide new data and emphasize the possible consequences to the in the Caribbean Sea, with the identification of dangerous elements (As, Cb, Pb, Hg, Ni and V), harmful to the marine ecosystem. Therefore, there is a need for strict control to reduce contamination of the Caribbean Sea and avoid risks to the ecosystem and public health, through suggestions of international public policies, through constant monitoring and the application of environmental recovery projects in this marine estuary

    Extensive colectomy in colorectal cancer and hereditary nonpolyposis colorectal cancer – long-term results

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    Background: Colorectal cancer survival is better in hereditary nonpolyposis colorectal cancer patients than in sporadic colorectal cancer patients and even for hereditary nonpolyposis colorectal cancer with colorectal cancer is not consensual that extensive colectomy is preferable to partial colectomy. This study analyzes and compares the long-term results of these two groups of patients submitted to curative subtotal colectomy or total colectomy. Methods: Between 2002 and 2018, 68 patients with colorectal cancer without familial adenomatous polyposis were submitted to a total or subtotal colectomy in a single tertiary center. The patients were divided in two groups: hereditary nonpolyposis colorectal cancer patients (with Amsterdam criteria) and sporadic colorectal cancer patients (the others). The presence of Amsterdam criteria for hereditary nonpolyposis colorectal cancer and germline mutation for mismatch repair genes was confirmed by clinical records. Results and survival were analyzed following surgery. Results: We obtained a sporadic colorectal cancer group with 31 patients and a hereditary nonpolyposis colorectal cancer group with 37 patients. The two groups differ in age but not in gender, tumor stage or surgical morbidity. The overall survival and disease-free survival were good in both groups but even better for hereditary nonpolyposis colorectal cancer group with statistical significance when comparing the two groups. Conclusion: Total or subtotal colectomy for colorectal cancer provides a good survival. These surgical procedures should be considered the first option for colorectal cancer in young hereditary non polyposis colorectal cancer patients. In those cases, they provide good long-term results, avoiding the risk of metachronous colorectal cancer and the surveillance is restricted only to the remaining need for rectum.info:eu-repo/semantics/publishedVersio

    Assessment of squash seed vigor using computerized image analysis.

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    Este trabalho procurou verificar a eficiência do SVIS® (Seed Vigor Imaging System) para determinar o vigor de sementes de abóbora colhidas durante diferentes estádios de maturação. Utilizou-se a cultivar híbrida Jabras, proveniente do cruzamento entre Cucurbita maxima (linhagem feminina) e Cucurbita moschata (linhagem masculina)

    A Model of Quark and Lepton Masses I: The Neutrino Sector

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    If neutrinos have masses, why are they so tiny? Are these masses of the Dirac type or of the Majorana type? We are already familiar with the mechanism of how to obtain a tiny Majorana neutrino mass by the famous see-saw mechanism. The question is: Can one build a model in which a tiny Dirac neutrino mass arises in a more or less "natural" way? What would be the phenomenological consequences of such a scenario, other than just merely reproducing the neutrino mass patterns for the oscillation data? In this article, a systematic and detailed analysis of a model is presented, with, as key components, the introduction of a family symmetry as well as a new SU(2) symmetry for the right-handed neutrinos. In particular, in addition to the calculations of light neutrino Dirac masses, interesting phenomenological implications of the model will be presented.Comment: 25 (single-spaced) pages, 11 figures, corrected some typos in Table I, added acknowledgement

    Flavour physics of the RS model with KK masses reachable at LHC

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    The version of the higher-dimensional Randall-Sundrum (RS) model with matter in the bulk, which addresses the gauge hierarchy problem, has additional attractive features. In particular, it provides an intrinsic geometrical mechanism that can explain the origin of the large mass hierarchies among the Standard Model fermions. Within this context, a good solution for the gauge hierarchy problem corresponds to low masses for the Kaluza-Klein (KK) excitations of the gauge bosons. Some scenarios have been proposed in order to render these low masses (down to a few TeV) consistent with precision electroweak measurements. Here, we give specific and complete realizations of this RS version with small KK masses, down to 1 TeV, which are consistent with the entire structure of the fermions in flavour space: (1) all the last experimental data on quark/lepton masses and mixing angles (including massive neutrinos of Dirac type) are reproduced, (2) flavour changing neutral current constraints are satisfied and (3) the effective suppression scales of non-renormalizable interactions (in the physical basis) are within the bounds set by low energy flavour phenomenology. Our result, on the possibility of having KK gauge boson modes as light as a few TeV, constitutes one of the first theoretical motivations for experimental searches of direct signatures at the LHC collider, of this interesting version of the RS model which accommodates fermion masses.Comment: 27 pages, Latex file. References and comments adde
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