1,932 research outputs found
Towards a Holistic Cloud System with End-to-End Performance Guarantees
Computing technologies are undergoing a relentless evolution from both the hardware and software sides, incorporating new mechanisms for low-latency networking, virtualization, operating systems, hardware acceleration, smart services orchestration, serverless computing, hybrid private-public Cloud solutions and others. Therefore, Cloud infrastructures are becoming increasingly attractive for deploying a wider and wider range of applications, including those with more and more stringent timing constraints, like the emerging use case of deploying time-critical applications. However, despite the availability of a number of public Cloud offerings, and of products (or open-source suites) for deploying in-house private Cloud infrastructures, still there are no solutions readily available for managing time-critical software components with predictable end-to-end timing requirements in the range of hundreds or even tens of milliseconds. The goal of this discussion is to present the multi-domain challenges associated with orchestrating a holistic Cloud system with endto- end guarantees, which is the subject of my current PhD investigations
Microdeformation in Vredefort rocks; evidence for shock metamorphism
Planar microdeformations in quartz from basement or collar rocks of the Vredefort Dome have been cited for years as the main microtextural evidence for shock metamorphism in this structure. In addition, Schreyer describes feldspar recrystallization in rocks from the center of the Dome as the result of transformation of diaplectic glass, and Lilly reported the sighting of mosaicism in quartz. These textural observations are widely believed to indicate either an impact or an internally produced shock origin for the Vredefort Dome. Two types of (mostly sub) planar microdeformations are displayed in quartz grains from Vredefort rocks: (1) fluid inclusion trails, and (2) straight optical discontinuities that sometimes resemble lamellae. Both types occur as single features or as single or multiple sets in quartz grains. Besides qualitative descriptions of cleavage and recrystallization in feldspar and kinkbands in mica, no further microtextural evidence for shock metamorphism at Vredefort has been reported to date. Some 150 thin sections of Vredefort basement rocks were re-examined for potential shock and other deformation effects in all rock-forming minerals. This included petrographic study of two drill cores from the immediate vicinity of the center of the Dome. Observations recorded throughout the granitic core are given along with conclusions
Seed longevity chart to predict viability of corn seed during open storage.
The simplified equation Vt = Vi – tg E.p is to predict the percentage of viability of any corn (Zea mays L.) seed lot after any period of time under open storage conditions. Based upon that equation, the objective of this work was to set a practical seed longevity chart to predict viability of corn seed lot during storage. From data of five corn seed lots stored at Sete Lagoas, MG, the value of the storage index (V) was calculated. This value (V = 120 days) corresponded exactly to the time taken in days for the initial germination of corn seeds stored to fall to a certain germination value observed in the accelerated aging test. Once the storage index (V) is estimated, the viability chart which illustrates the relationship between initial germination, seed deterioration rate and storagecondition over time can be constructed. The chart can be used by any seed producer once the value of storage index (V) in situ is determined. The application of the seed viability chart to short-term seed storage seems to be promising for seed growers. This predictive model is the first attempt of incorporating the effect of seed quality, the deterioration rate and the storage environmental conditions (temperature and relative humidity) into a seed longevity chart of an open storage. A equação simplificada Vt = Vi - tgb. p foi desenvolvida para predizer a perda da viabilidade de semente de milho (Zea mays L.) em armazém convencional. Com base nessa equação, o objetivo deste trabalho foi desenhar um gráfico prático de longevidade da semente, para predizer a viabilidade dos lotes de semente de milho durante o armazenamento. Cinco lotes de milho híbrido BRS 201 foram armazenados nas condições ambientais de Sete Lagoas, MG, e o valor do índice de armazenamento (s) foi calculado. Esse valor (s) de 120 dias corresponde ao tempo que a semente levou para sua viabilidade inicial cair a uma certa porcentagem de germinação, no teste de envelhecimento acelerado, para os lotes de milho. Uma vez que o índice (s) é determinado, o gráfico de longevidade pode ser construído, o qual ilustra a relação entre a germinação inicial, a taxa de deterioração e as condições do armazenamento. Aplica-se o gráfico com informações úteis, desde que o valor do índice de armazenamento seja calculado para as condições in situ do seu armazém. A aplicação do gráfico de longevidade para médio prazo de armazenamento é promissora para os produtores de sementes. Esse modelo predicante é a primeira tentativa de incorporar o efeito da qualidade da semente, a taxa de deterioração e as condições de armazenamento convencional num gráfico, para predizer a longevidade da semente
Efeito do matricondicionamento integrado com controle quimico e biologico na emergencia de plântulas e na produtividade de milho.
Uma das principais causas da baixa produtividade de milho (Zea mays L.) é a qualidade de semente, que afeta o estande inicial e a população de plantas. O objetivo deste trabalho foi avaliar os efeitos da qualidade da semente e da integração do condicionamento matricial (MC) com o tratamento químico (Captan@) e biológico Kodiak@ (Bacillus subtilis) na emergência de plântulas e na produtividade de milho, nas condições tropicais de Sete Lagoas, MG, e de estresses de frio, em Ponta Grossa, PR. Dois experimentos foram conduzidos na Embrapa Milho e Sorgo, em Sete Lagoas, em 1996 e 1998, e um em Ponta Grossa, PR, em 1997. Sementes de milho híbrido foram condicionadas com Micro-Cel E na presença de B. subtilis (600 mg kg-1 de sementes), B. subtilis + Captan@ e ácido giberélico (GA4+7 100 uM). Dois lotes de sementes, com germinação de 95% e 85%, foram condicionados à razão de 20: 5: 20, a 22°C, por 48 horas, com MC e na presença de Bacillus. Os parâmetros estudados foram: emergência de plântulas aos 10 e 20 dias, estande final, índice de velocidade de emergência (IVE), número de espigas ha-1, produção de grãos e de espigas ha-1. A qualidade inicial do lote de sementes foi fundamental no estabelecimento do estande e na produtividade de milho; a integração do MC com o tratamento químico e biológico beneficiam a qualidade da semente e a produtividade de milho, especialmente em condições de estresse. O condicionamento com GA4+7 não favoreceu a produtividade de milho e a integração do condicionamento matricial (MC) com o tratamento biológico (Bacillus) mostrou-se efetiva em aumentar o vigor das sementes de baixa qualidade
Efeito da integração do matricondicionamento com o tratamento de sementes sobre a emergência de plântulas e a produtividade de milho.
Número especial. Edição dos resumos do XIII Congresso Brasileiro de Sementes, Londrina, 2003
Considerações estatísticas sobre os testes de pureza genética em milho e soja.
Número especial. Edição dos resumos do XIII Congresso Brasileiro de Seentes, Londrina, 2003
Seed germination inhibition of angico vermelho [Anadenanthera peregrina (Benth.) Speg.] by desication and ABA treatment.
Priority-Driven Differentiated Performance for NoSQL Database-As-a-Service
Designing data stores for native Cloud Computing services brings a number of challenges, especially if the Cloud Provider wants to offer database services capable of controlling the response time for specific customers. These requests may come from heterogeneous data-driven applications with conflicting responsiveness requirements. For instance, a batch processing workload does not require the same level of responsiveness as a time-sensitive one. Their coexistence may interfere with the responsiveness of the time-sensitive workload, such as online video gaming, virtual reality, and cloud-based machine learning. This paper presents a modification to the popular MongoDB NoSQL database to enable differentiated per-user/request performance on a priority basis by leveraging CPU scheduling and synchronization mechanisms available within the Operating System. This is achieved with minimally invasive changes to the source code and without affecting the performance and behavior of the database when the new feature is not in use. The proposed extension has been integrated with the access-control model of MongoDB for secure and controlled access to the new capability. Extensive experimentation with realistic workloads demonstrates how the proposed solution is able to reduce the response times for high-priority users/requests, with respect to lower-priority ones, in scenarios with mixed-priority clients accessing the data store
Validation of a bioanalytical method for the determination of synthetic and natural cannabinoids (New psychoactive substances) in oral fluid samples by means of hplc-ms/ms
New psychoactive substances (NPS) represent an important focus nowadays and are continually produced with minimal structural modifications in order to circumvent the law and increase the difficulty of identifying them. Moreover, since there are a high number of different compounds, it is arduous to develop analytical screening and/or confirmation methods that allow the identification and quantification of these compounds. The aim of this work is to develop and validate a bioanalytical method for detecting new synthetic drugs in biological samples, specifically oral fluid, using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) with minimal sample pretreatment. Oral fluid samples were simply centrifuged and denaturized with different rapid procedures before injection into the LC-MS/MS system. Calibration curves covered a linear concentration range from LOQ to 100 ng/mL. Validation parameters such as linearity, precision, accuracy, selectivity, matrix effect and thermal stability were evaluated and showed satisfactory results, in accordance with US Food & Drug Administration guidelines. The inter-day analytical bias and imprecision at two levels of quality control (QC) were within ±15% for most compounds. This method was able to identify and calculate the concentration of 10 NPS validated in this biological sample, even in the presence of matrix effect
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