Quinoa (Chenopodium quinoa Willd.) has been cultivated for more than 7,000 years in the mountain regions (Andes Mountains) of South America. Five ecotypes differing in their phenology, morphology and ...stress resistance can be found. One of these ecotypes corresponds to the coastal ecotype, which is cultivated mainly in Chile. Little information is available regarding the response of this ecotype to nitrogen (N) fertilization. In the present study, three N fertilization doses (low: 30, adequate: 140 and high: 280 kg ha-1) were evaluated in plants grown in containers. Seed yield and quality attributes, including seed weight, nitrate content, germination, and seed longevity, were evaluated. These results indicate that increasing N fertilization promotes increases in seed yield and weight. In terms of seed quality, although the fertilization treatments did not affect germination, seed longevity was reduced by increasing the N fertilization dose.
A Secure P2P Architecture for Video Distribution López-Fuentes, Francisco de Asís; Orta-Cruz, Carlos Alberto
Proceedings of the First International Workshop on Internet-Scale Multimedia Management,
11/2014
Conference Proceeding
Currently, video demand has increased significantly, as well as sites that provide this type of service. There is also a wide range of devices from which video requests are performed. Due to these ...facts, video providers use different video coding techniques that allow adapting the video both to variable conditions of the network as to heterogeneity of devices. A vast majority of video applications are based on the client-server model, which means that system maintenance is very expensive. An alternative to client-server model are the P2P (peer-to-peer) networks, which have attractive features for broadcast video, such as scalability and low cost of implementation. However, a major limitation to the use of P2P infrastructures for content distribution is security. This is because most of the sites do not consider authentication methods and contents protection. This paper proposes a P2P architecture for video distribution using scalable video coding techniques and security strategies such as encryption and authentication.
In this contribution we simulate network coding and evaluate its benefits for streaming video over P2P networks. Network coding has emerged as a promise technique in the information theory field. ...This novel technique has shown several benefits in the communication networks related to throughput, security and resources optimization. In this work, we implement network coding for a multi-source P2P scenario. The video is encoded in the sources, while the intermediate nodes implement network coding before forwarding the encoded packets to the end nodes. The received packets are decoded in each receiving peer in order to recovery the original video. Our scheme is implemented under the H.264/MPEG-4 AVC compression standard and using the network simulator (NS-2). We evaluate our scheme in terms of overall throughput, packet loss and video quality. Results show that these parameters can be improved in P2P video streaming systems by using network coding.
Objective
To compare detectability of hyperfunctioning parathyroid tissue (HPT) by digital and analog 18F-fluorocholine PET/CT in patients with primary hyperparathyroidism and negative/inconclusive ...99mTc-MIBI scintigraphy-SPECT/CT.
Materials and methods
Thirty-three patients with primary hyperparathyroidism and negative/inconclusive 99mTc-MIBI scintigraphy-SPECT/CT were prospectively included. All patients accepted to be scanned by digital and analog PET/CT in the same imaging session after a single injection of 18F-fluorocholine. Three nuclear medicine physicians evaluated the digital and analog PET/CT datasets to assess the detection rate of HPT. Maximum standard uptake values (SUVmax) of HPT and locoregional lymph nodes were measured in both systems.
Results
HPT was detected in 30/33 patients by the digital system, whereas it was detected in 22/33 patients by the analog system (
p
< 0.01). Moreover, in 21 of these 33 patients, both systems detected one focal 18F-fluorocholine uptake, and in one patient the digital system detected two foci. Histopathology demonstrated HPT in 32 patients and it was inconclusive in one patient. The digital PET/CT detected HPT in 29 of the 32 patients, and the analog system in 22 of the 32 (
p
< 0.01). All HPT suspected lesions resected and detected only by the digital system (
n
= 8) were < 10 mm (7.5 ± 1.3 mm), while those detected by both systems (
n
= 22) were > 10 mm (13 ± 3.8 mm). SUVmax of HPT lesions was significantly higher than SUVmax of locoregional lymph node independently of the PET/CT system used (4.5 ± 1.9 vs. 2.9 ± 1.3,
p
< 0.0001).
Conclusions
Digital PET/CT offers superior performance over analog system in patients with suspected HPT and previous negative/inconclusive imaging examinations, particularly in sub-centimeter lesions. SUVmax can help in the differentiation between HTP and locoregional lymph nodes.
Rhizobia are soil proteobacteria able to establish nitrogen-fixing symbiosis with host legumes. This symbiotic interaction, which is highly important from ecological and agronomical points of view ...since it allows growth of legumes in soils poor in nitrogen, requires a complex interchange of molecular signals between both symbionts. The production of rhizobial molecular signals is elicited by flavonoids, which are phenolic compounds exuded by legume roots. Recent work has shown that osmotic stress can also promote the formation of symbiotic signals in some rhizobia. In this work, we show that this is also the case for Sinorhizobium fredii HH103, a rhizobial strain able to establish symbiosis with hundreds of legumes, including the very important crop, soybean. Non-ionic osmotic stress, which can be encountered by the bacterium in the rhizosphere or inside the legume host, affected the expression of hundreds of bacterial genes and, consequently, influenced diverse bacterial traits, including the production of symbiotic signals and certain characteristics that may be relevant for successful interaction with the host: motility, production of the phytohormone indole acetic acid, and production of molecules involved in bacterial cell-to-cell communication. Thus, our work provides new evidence of how stress can promote rhizobia-legume symbiosis. (1) Background: Some rhizobia, such as Rhizobium tropici CIAT 899, activate nodulation genes when grown under osmotic stress. This work aims to determine whether this phenomenon also takes place in Sinorhizobium fredii HH103. (2) Methods: HH103 was grown with and without 400 mM mannitol. β-galactosidase assays, nodulation factor extraction, purification and identification by mass spectrometry, transcriptomics by RNA sequencing, motility assays, analysis of acyl-homoserine lactones, and indole acetic acid quantification were performed. (3) Results: Non-ionic osmotic stress induced the production of nodulation factors. Forty-two different factors were detected, compared to 14 found in the absence of mannitol. Transcriptomics indicated that hundreds of genes were either activated or repressed upon non-ionic osmotic stress. The presence of 400 mM mannitol induced the production of indole acetic acid and acyl homoserine lactones, abolished swimming, and promoted surface motility. (4) Conclusions: In this work, we show that non-ionic stress in S. fredii HH103, caused by growth in the presence of 400 mM mannitol, provokes notable changes not only in gene expression but also in various bacterial traits, including the production of nodulation factors and other symbiotic signals.
La elevada importancia que ha tenido el desarrollo y utilización adecuada de la radiología (actualmente imagenología) para el diagnóstico de diversas afecciones médicas en el presente siglo, ...especialmente en las últimas décadas, unida a la ausencia de investigaciones relacionadas con el surgimiento y evolución de dicha especialidad en nuestra localidad, sustenta la necesidad de brindar un mayor conocimiento de la historia de la Radiología en Cienfuegos. El objetivo de este estudio es exponer los elementos relacionados con el surgimiento y desarrollo de la Radiología en Cuba, particularmente en Cienfuegos, así como los beneficios que ha traído a la población de esta ciudad. Para ello se realizó un estudio cualitativo, de perfil histórico y descriptivo. Se exponen aspectos relacionados con la asistencia y la docencia del personal no médico y se hace alusión a diversas personalidades relevantes vinculadas a esta actividad. El surgimiento de la Radiología en la provincia se remonta a los primeros años de la segunda década del 1900, sin embargo, no fue hasta después del triunfo de la revolución en 1959, que experimentó un verdadero avance tecnológico.
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