1,353 research outputs found

    Comparisons of luminaires: Efficacies and system design

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    Lighting designs for architectural (aesthetic) purposes, vision and safety, and plant growth have many features in common but several crucial ones that are not. The human eye is very sensitive to the color (wavelength) of light, whereas plants are less so. There are morphological reactions, particularly to the red and blue portions of the light spectrum but, in general, plants appear to accept and use light for photosynthesis everywhere over the PAR region of the spectrum. In contrast, the human eye interprets light intensity on a logarithmic scale, making people insensitive to significant differences of light intensity. As a rough rule, light intensity must change by 30 to 50% for the human eye to recognize the difference. Plants respond much more linearly to light energy, at least at intensities below photosynthetic saturation. Thus, intensity differences not noticeable to the human eye can have significant effects on total plant growth and yield, and crop timing. These factors make luminaire selection and lighting system design particularly important when designing supplemental lighting systems for plant growth. Supplemental lighting for plant growth on the scale of commercial greenhouses is a relatively expensive undertaking. Light intensities are often much higher than required for task (vision) lighting, which increases both installation and operating costs. However, and especially in the northern regions of the United States (and Canada, Europe, etc.), supplemental lighting during winter may be necessary to produce certain crops (e.g., tomatoes) and very useful to achieve full plant growth potential and crop timing with most other greenhouse crops. Operating costs over the life of a luminaire typically will exceed the initial investment, making lighting efficacy a major consideration. This report reviews tests completed to evaluate the efficiencies of various commercially-available High-Pressure Sodium luminaires, and then describes the results of using a commercial lighting design computer program, Lumen-Micro, to explore how to place luminaires within greenhouses and plant growth chambers to achieve light (PAR) uniformity and relatively high lighting efficacies. Several suggestions are presented which could encourage systematic design of plant lighting systems

    Escola ambiental: transferência de tecnologias geradas pela Embrapa para a segurança alimentar e a valorização da agricultura urbana nas escolas da cidade de Belém, Pará.

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    Organizar e qualificar os conhecimentos e tecnologias sobre educação ambiental, segurança alimentar, cultivo de hortas, formação de pomares e a criação de abelhas sem ferrão adaptáveis ao cultivo em escolas; Implantar módulos de cultivos de hortifrutigrangeiros, de pomares e de criação de abelhas sem ferrão para demonstração de tecnologias visando contribuir para a formação educacional sobre educação ambiental e segurança alimentar; Desenvolver ações de comunicação para disseminar as iniciativas e os resultados do projeto; Capacitar agentes multiplicadores (professores, funcionários, alunos, familiares de alunos e etc.) para desenvolvimento da agricultura urbana através de ação educativa e melhoria de hábitos alimentares; Monitorar e avaliar os resultados e impactos das ações de TT

    Au/Zn Contacts to rho-InP: Electrical and Metallurgical Characteristics and the Relationship Between Them

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    The metallurgical and electrical behavior of Au/Zn contacting metallization on p-type InP was investigated as a function of the Zn content in the metallization. It was found that ohmic behavior can be achieved with Zn concentrations as small as 0.05 atomic percent Zn. For Zn concentrations between 0.1 and 36 at. percent, the contact resistivity rho(sub c) was found to be independent of the Zn content. For low Zn concentrations the realization of ohmic behavior was found to require the growth of the compound Au2P3 at the metal-InP interface. The magnitude of rho(sub c) is shown to be very sensitive to the growth rate of the interfacial Au2P3 layer. The possibility of exploiting this sensitivity to provide low resistance contacts while avoiding the semiconductor structural damage that is normally attendant to contact formation is discussed

    Produção sustentável de pimenta-do-reino em tutor vivo de gliricídia no estado do Pará: bases econômicas e de qualidade.

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    A pimenta-do-reino é a mais importante especiaria comercializada no mundo e como se trata de uma commodity, a tendência do mercado é a comercialização de produtos originados de sistemas de produção sustentáveis, com contribuição relevante do uso de tutor vivo de Gliricidia sepium L. em substituição ao estacão (tutor morto), na produção de pimenta-do-reino. Entretanto, a adoção desta tecnologia é limitada em decorrência da escassez de informações (irrigação, espaçamento, nutrição, manejo entre outros fatores de produção) sobre as interações entre o comportamento das cultivares de pimenteira-do-reino a esse tipo de tutor, para consolidação de um sistema de produção sustentável. Portanto, o estudo consiste em identificar as condições adequadas de irrigação e adubação em que a cultura da pimenteira-do-reino cultivada em tutor vivo tenha as exigências hídricas e nutricionais atendidas para a produção com qualidade e viabilidade econômica no Nordeste Paraense. Com o uso da irrigação, assinalou-se uma menor demanda hídrica com o uso de Gliricidia sepium no sistema de irrigação com duas linhas, e menor custo. A implantação do tutor vivo de gliricídia, com custos menores, comparados ao tutor morto, assegura recursos financeiros para a adoção de irrigação. No estabelecimento da cultura, referenda-se os níveis de adubação mínimos (60g de uréia, 40g de P2O5 e 70g de K2O por planta), que equivalem à recomendação de adubação na literatura. A qualidade da pimenta-do-reino produzida com o uso da gliricídia obteve incremento com relação aos índices de densidade, extrato etéreo e piperina. Os resultados desse estudo indicam evidentes contribuições do uso de tutor vivo de gliricídia na circularidade econômica da cadeia da pimenta-do-reino. Neste cenário, recomenda-se o estabelecimento de políticas públicas, voltadas ao desenvolvimento e validação de inovações tecnológicas que assegurem o incremento de produtividade, qualidade do produto e redução de riscos na cadeia produtiva da pimenta-do-reinoTese (Doutorado em Agronomia) - Universidade Federal Rural da Amazônia, Belém, PA. Orientador: Joaquim Alves de Lima Junior; Coorientador: Oriel Filgueira de Lemos, Embrapa Amazônia Oriental

    Translocation as a Novel Approach to Study Effects of a New Breeding Habitat on Reproductive Output in Wild Birds

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    Environmental conditions under which species reproduce have major consequences on breeding success and subsequent fitness. Therefore breeding habitat choice is ultimately important. Studies rarely address the potential fitness pay-offs of alternative natural breeding habitats by experimental translocation. Here we present a new tool to study fitness consequences of free living birds in different habitats. We translocated a migratory passerine, the pied flycatcher (Ficedula hypoleuca), to a novel site, where pairs were subjected to a short stay (2–4 days) in a nest box-equipped aviary before being released. We show that it is technically possible to retain birds in the new area for breeding, allowing the study of reproductive consequences of dispersal under natural conditions. The translocation resulted in an extension of the interval between arrival and egg laying of four days, highlighting the importance of having an adequate control group. Clutch size and nestling parameters did not differ significantly between translocated and unmanipulated females, which suggests that the procedure did not affect birds in their reproductive performance later on. This method could be applied broadly in evolutionary and ecological research, e.g., to study the potential fitness benefits and costs for dispersing to more northern latitudes as a way of adapting to climate change

    Discussing sexual health in spinal care

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    Abstract BACKGROUND: The possible detrimental effects of spinal disease on sexual health are widely recognized; however, it is not known to what extent neurosurgeons discuss this topic with their patients. The aim of this study is to identify knowledge, attitude and practice patterns of neurosurgeons counseling their patients about sexual health. METHODS: All members of the Dutch Association of Neurosurgery (neurosurgeons and residents) were sent a questionnaire addressing their attitudes, knowledge and practice patterns regarding discussing sexual health. RESULTS: Response rate was 62 % with 89 questionnaires suitable for analysis. The majority of participants (83 %) were male; mean age, 42.4 years. The mean experience in neurosurgical practice was 9 years. Respondents assumed that in 34 % of their patients, sexual health was affected due to spinal disease. The majority of respondents (64 %) stated that responsibility for discussing sexual health lies (partly) with the neurosurgeon; however, 73 % indicated to (almost) never do this. The main reasons for not discussing sexual health were patients' old age (42 %), lack of knowledge (38 %) and lack of patients' initiative to bring up the subject (36 %). Twenty-six percent indicated lack of time as a reason. There was no evidence for gender or doctor's age discordance as important barriers. Fifty percent of participants wished to gain more knowledge on discussing sexual health with patients. CONCLUSION: This study shows that despite high prevalence of sexual dysfunction (SD) in spinal patients, counseling about sexual health is not often done in neurosurgical care. More training on sexual health counseling early in the residency program seems critical. By initiating the discussion, clinicians who deal with spinal patients have the potential to detect sexual dysfunction (SD) and to refer adequately when necessary, thereby improving overall quality of life of their patients. KEYWORDS: Cauda equina syndrome; Counseling; Patient care; Sexual dysfunction; Spinal cord injury GynecologyCervix cance

    Aprender fazendo: formação de multiplicadores comunitários com uso de tecnologias da Embrapa.

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    Esta sistematização teve como intenção, entre outros aspectos, servir como um registro de um modelo diferenciado de abordagem em um segmento de público não usual da Embrapa. Deve servir como balizamento para a Unidade da Embrapa Amazônia Oriental no tocante às atividades de TT e pode ser utilizada, também, por parceiros institucionais, por exemplo: Empresa de Assistência Técnica e Extensão Rural (Emater) e sistema de Assessoria Técnica, Social e Ambiental à Reforma Agrária (Ates); universidades, Serviço Brasileiro de Apoio às Micro e Pequenas Empresas (Sebrae), além dos atores envolvidos.bitstream/item/176438/1/COLECAO-SISTEMATIZACAO-EXPERIENCIAS-vol-6.pd

    A novel semi auto-segmentation method for accurate dose and NTCP evaluation in adaptive head and neck radiotherapy

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    Background and purpose: Accurate segmentation of organs-at-risk (OARs) is crucial but tedious and time-consuming in adaptive radiotherapy (ART). The purpose of this work was to automate head and neck OAR-segmentation on repeat CT (rCT) by an optimal combination of human and auto-segmentation for accurate prediction of Normal Tissue Complication Probability (NTCP). Materials and methods: Human segmentation (HS) of 3 observers, deformable image registration (DIR) based contour propagation and deep learning contouring (DLC) were carried out to segment 15 OARs on 15 rCTs. The original treatment plan was re-calculated on rCT to obtain mean dose (D-mean) and con-sequent NTCP-predictions. The average Dmean and NTCP-predictions of the three observers were referred to as the gold standard to calculate the absolute difference of D-mean and NTCP-predictions (vertical bar AD(mean)vertical bar and vertical bar ANTCP vertical bar). Results: The average vertical bar AD(mean)vertical bar of parotid glands in HS was 1.40 Gy, lower than that obtained with DIR and DLC (3.64 Gy, p < 0.001 and 3.72 Gy, p < 0.001, respectively). DLC showed the highest vertical bar AD(mean)vertical bar in middle Pharyngeal Constrictor Muscle (PCM) (5.13 Gy, p = 0.01). DIR showed second highest vertical bar AD(mean)vertical bar in the cricopharyngeal inlet (2.85 Gy, p = 0.01). The semi auto-segmentation (SAS) adopted HS, DIR and DLC for segmentation of parotid glands, PCM and all other OARs, respectively. The 90th percentile vertical bar ANTCP vertical bar was 2.19%, 2.24%, 1.10% and 1.50% for DIR, DLC, HS and SAS respectively. Conclusions: Human segmentation of the parotid glands remains necessary for accurate interpretation of mean dose and NTCP during ART. Proposed semi auto-segmentation allows NTCP-predictions within 1.5% accuracy for 90% of the cases. (C) 2021 The Author(s). Published by Elsevier B.V

    Technical Note: 4D cone-beam CT reconstruction from sparse-view CBCT data for daily motion assessment in pencil beam scanned proton therapy (PBS-PT)

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    Purpose: The number of pencil beam scanned proton therapy (PBS-PT) facilities equipped with cone-beam computed tomography (CBCT) imaging treating thoracic indications is constantly rising. To enable daily internal motion monitoring during PBS-PT treatments of thoracic tumors, we assess the performance of Motion-Aware RecOnstructiOn method using Spatial and Temporal Regularization (MA-ROOSTER) four-dimensional CBCT (4DCBCT) reconstruction for sparse-view CBCT data and a realistic data set of patients treated with proton therapy. Methods: Daily CBCT projection data for nine non-small cell lung cancer (NSCLC) patients and one SCLC patient were acquired at a proton gantry system (IBA Proteus® One). Four-dimensional CBCT images were reconstructed applying the MA-ROOSTER and the conventional phase-correlated Feldkamp-Davis-Kress (PC-FDK) method. Image quality was assessed by visual inspection, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and the structural similarity index measure (SSIM). Furthermore, gross tumor volume (GTV) centroid motion amplitudes were evaluated. Results: Image quality for the 4DCBCT reconstructions using MA-ROOSTER was superior to the PC-FDK reconstructions and close to FDK images (median CNR: 1.23 [PC-FDK], 1.98 [MA-ROOSTER], and 1.98 [FDK]; median SNR: 2.56 [PC-FDK], 4.76 [MA-ROOSTER], and 5.02 [FDK]; median SSIM: 0.18 [PC-FDK vs FDK], 0.31 [MA-ROOSTER vs FDK]). The improved image quality of MA-ROOSTER facilitated GTV contour warping and realistic motion monitoring for most of the reconstructions. Conclusion: MA-ROOSTER based 4DCBCTs performed well in terms of image quality and appear to be promising for daily internal motion monitoring in PBS-PT treatments of (N)SCLC patients
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