A note on parallel and pipeline computation of fast unitary transforms

The parallel and pipeline organization of fast unitary transform algorithms such as the Fast Fourier Transform are discussed. The efficiency is pointed out of a combined parallel-pipeline processor of a transform such as the Haar transform in which 2 to the n minus 1 power hardware butterflies generate a transform of order 2 to the n power every computation cycle

Towards the Assessment of an Ecological Index for Quantifying Sustainability of Day Life. A Case Study of the Environmental Consequences of Dietary and Transport in a Standard Workday

e-Conferenc

Four-dimensional pseudo-Riemannian homogeneous Ricci solitons

We consider four-dimensional homogeneous pseudo-Riemannian manifolds with non-trivial isotropy and completely classify the cases giving rise to non-trivial homogeneous Ricci solitons. In particular, we show the existence of non-compact homogeneous (and also invariant) pseudo-Riemannian Ricci solitons which are not isometric to solvmanifolds, and of conformally flat homogeneous pseudo-Riemannian Ricci solitons which are not symmetric.Comment: 16 pages; Final version, to appear in International Journal of Geometric Methods in Modern Physic

A practical method for gas changing time estimation using a simple gas-liquid mass transfer model

The present work explains a practical and simple method to calculate the gas changing time of anaerobic systems. It is substantiated under the physics of gas-liquid transfer theory and allows researchers to obtain an approximate value of gas changing time with few measurements of the gas composition in the outlet of the reactor. The only analytical equipment required is a gas analyzer, and calculations can be done using a spreadsheet. Along with the validation of the model, a short guide for its application in the laboratory is introduced. The model fits the experimental data with less than 1% error in the composition of the out-gas when no carbon dioxide is involved. This method will allow savings in valuable resources such as time and gases while providing greater comprehension of the characteristics of the gas-liquid transfer of the studied system

CDMA, OFDM, MC-CDMA, quel choix pour une voie descendante ?

Cet article propose une démarche comparative de différentes formes d'onde candidates pour une voie descendante de radiocommunications. Partant d'un formalisme général pour le DS-CDMA, l'OFDM et le MC-CDMA, les comportements de ces formes d'onde vis à vis d'erreurs de fréquence ou de bruit de phase sont analysés

Coupling dairy wastewaters for nutritional balancing and water recycling: sustainable heterologous 2-phenylethanol production by engineered cyanobacteria

Microalgae biotechnology is hampered by the high production costs and the massive usage of water during large-volume cultivations. These drawbacks can be softened by the production of high-value compounds and by adopting metabolic engineering strategies to improve their performances and productivity. Today, the most sustainable approach is the exploitation of industrial wastewaters for microalgae cultivation, which couples valuable biomass production with water resource recovery. Among the food processing sectors, the dairy industry generates the largest volume of wastewaters through the manufacturing process. These effluents are typically rich in dissolved organic matter and nutrients, which make it a challenging and expensive waste stream for companies to manage. Nevertheless, these rich wastewaters represent an appealing resource for microalgal biotechnology. In this study, we propose a sustainable approach for high-value compound production from dairy wastewaters through cyanobacteria. This strategy is based on a metabolically engineered strain of the model cyanobacterium Synechococcus elongatus PCC 7942 (already published elsewhere) for 2-phenylethanol (2-PE). 2-PE is a high-value aromatic compound that is widely employed as a fragrance in the food and cosmetics industry thanks to its pleasant floral scent. First, we qualitatively assessed the impact of four dairy effluents on cyanobacterial growth to identify the most promising substrates. Both tank-washing water and the liquid effluent of exhausted sludge resulted as suitable nutrient sources. Thus, we created an ideal buffer system by combining the two wastewaters while simultaneously providing balanced nutrition and completely avoiding the need for fresh water. The combination of 75% liquid effluent of exhausted sludge and 25% tank-washing water with a fine-tuning ammonium supplementation yielded 180 mg L−1 of 2-PE and a biomass concentration of 0.6 gDW L-1 within 10 days. The mixture of 90% exhausted sludge and 10% washing water produced the highest yield of 2-PE (205 mg L−1) and biomass accumulation (0.7 gDW L−1), although in 16 days. Through these treatments, the phosphates were completely consumed, and nitrogen was removed in a range of 74%–77%. Overall, our approach significantly valorized water recycling and the exploitation of valuable wastewaters to circularly produce marketable compounds via microalgae biotechnology, laying a promising groundwork for subsequent implementation and scale-up

Metodología de diseño e implementación de soluciones VOIP

El presente documento ilustra metodológicamente el diseño y la implementación de una solución VoIP, la cual integra la planta análoga (PBX)con el modulo de PBX del Elastix (IP-PBX), por medio de un Gatewayde VoIP. Con el producto de esta investigación, desarrollada por el grupo INTEGRA, se permite el uso de nuevos servicios enfocados en el óptimo uso de las redes (telefonía y datos) usando servicios adicionales, como son: servidor de fax, servidor de mensajería instantánea, control y reporte detallado de llamadas, grabaciones y servicios adicionales como la recepción de fax y buzón de mensajes al correo electrónico como archivos adjuntos

Multiparametric magnetic resonance imaging for the differential diagnosis between granulomatous prostatitis and prostate cancer: a literature review to an intriguing diagnostic challenge

Multiparametric magnetic resonance imaging (mpMRI) is currently the most effective diagnostic tool for detecting prostate cancer (PCa) and evaluating adenocarcinoma-mimicking lesions of the prostate gland, among which granulomatous prostatitis (GP) represents the most interesting diagnostic challenge. GP consists of a heterogeneous group of chronic inflammatory lesions that can be differentiated into four types: idiopathic, infective, iatrogenic, and associated with systemic granulomatous disease. The incidence of GP is growing due to the increase in endourological surgical interventions and the adoption of intravesical instillation of Bacillus Calmette-Guerin in patients with non-muscle invasive bladder cancer; therefore, the difficulty lies in identifying specific features of GP on mpMRI to avoid the use of transrectal prostate biopsy as much as possible

Anti-self-dual conformal structures with null Killing vectors from projective structures

Using twistor methods, we explicitly construct all local forms of four--dimensional real analytic neutral signature anti--self--dual conformal structures $(M,[g])$ with a null conformal Killing vector. We show that $M$ is foliated by anti-self-dual null surfaces, and the two-dimensional leaf space inherits a natural projective structure. The twistor space of this projective structure is the quotient of the twistor space of $(M,[g])$ by the group action induced by the conformal Killing vector. We obtain a local classification which branches according to whether or not the conformal Killing vector is hyper-surface orthogonal in $(M, [g])$. We give examples of conformal classes which contain Ricci--flat metrics on compact complex surfaces and discuss other conformal classes with no Ricci--flat metrics.Comment: 43 pages, 4 figures. Theorem 2 has been improved: ASD metrics are given in terms of general projective structures without needing to choose special representatives of the projective connection. More examples (primary Kodaira surface, neutral Fefferman structure) have been included. Algebraic type of the Weyl tensor has been clarified. Final version, to appear in Commun Math Phy