Equacions de transport generalitzades per a fluxos turbulents

Es dedueixen les equacions de transport en forma tensorial per a fluxos turbulents en coordenades generalitzades. Es presenten les equacions de continuïtat, les equacions de Navier-Stokes i les equacions de Reynolds, així com les equacions de transport de la vorticitat, de 1'energia cinètica turbulenta i de la velocitat de dissipació de 1'energia turbulenta mitjanes.The transport equation for turbulent flows are deduced in tensorial notation and for a generalized coordinate system. The equations of continuity, Navier-Stokes and Reynolds, as well as the transport equations for mean vorticity , turbulent kinetic energy and dissipation rate are presented

La revolució musical del segle XX dins la tradició del blues, com a innovació docent

Des de fa unes dècades la denominada cultura "pop" ha entrat en els cànons de referència pel que fa a la comunicació mediàtica i a l'expressió artística de la segona meitat del segle XX. L'acceleració cronèmica dins aquest procés històric ha donat avui prou perspectiva com per permetre tractar aquest fenòmen sociocultural en profunditat i de forma objectiva, en tant que forma part dels imaginaris col・lectius de la societat actual. Havent tractat aquesta temàtica al llarg d'anys, la qüestió estava en entendre si una aproximació al que, de forma genèrica, i no massa afortunada, ha vingut denominant-se cultura del "pop-rock", tindria prou solvència com per ser objecte de recerca a través d'una activitat docent universitària. Es així que, seguint el model d'altres universitats (Florida, Cambridge, Bourgogne, etc) i considerant els referents actuals en matèria de poètica, que formen ja part dels estudis de filologia anglesa (Bob Dylan, Jim Morrison, Lennon-McCartney, etc), fa set anys s'impartí un curs d'estiu en aquesta universitat (ICE), gairebé a tall de prova pilot. El resultat fou altament satisfactori i es demostrà no solament la viabilitat d'incloure aquesta temàtica dins el ventall d'estudis universitaris, sinó també la necessitat de tractar aquests aspectes culturals i psicosocials que formen part de la nostra societat. A part els anys de recerca sobre el tema, d'ençà la primera experiència docent han estat realitzats set cursos d'estiu, de caràcter introductori i tres a Cultura en Viu, aprofundint la temàtica i tractant temes específics. Es així que a través d'un doble marc teòric (antropologia i semiòtica), complementaris del musical, s'ha fet possible entendre una tradició musical que començà fa més d'un segle al delta del Mississippi.For years, the so called "pop culture" has been a strong, and even canonical, cultural reference in which is concerned to media communication, as an alternative way of artistic expression in the second half of the 20th century. Today we have a wider perspective to deal with that specific topic and to work in a deep approach by focusing on the collective images of each generation. Anyway, at first sight, the question was if such a controversial topic would cope with an educational university activity. This is the reason why we decided to follow the models of different universities dealing with the same topics, mainly Florida, Cambridge and Bourgogne, while considering, on the other hand, the present inclusion of some pop-rock performers (Bob Dylan, Jim Morrison, Lennon & McCartney, etc) in the syllabus of poetry in English philology. Thus, we started a course just a pilot experience in the UAB summer courses (ICE) and the result was highly satisfactory. Other experiences followed till today, through the same department and also Cultura en Viu. As a result of that, dealing with a double theoretic frame (anthropology and semiotics), as well as music, of course, we have been involved in the diffussion of a musical tradition that started in the Mississippi delta long time ago

HIV-1 Infection and the PPARγ-Dependent Control of Adipose Tissue Physiology

PPARγ is a ligand-dependent master transcription factor controlling adipocyte differentiation as well as multiple biological processes taking place in other cells present in adipose tissue depots such as macrophages. Recent research indicates that HIV-1 infection-related events may alter adipose tissue biology through several mechanisms involving PPARγ, ranging from direct effects of HIV-1-encoded proteins on adipocytes to the promotion of a proinflammatory environment that interferes with PPARγ actions. This effect of HIV-1 on adipose tissue cells can occur even in the absence of direct infection of adipocytes, as soluble HIV-1-encoded proteins such as Vpr may enter cells and inhibit PPARγ action. Moreover, repression of PPARγ actions may relieve inhibitory pathways of HIV-1 gene transcription, thus enhancing HIV-1 effects in infected cells. HIV-1 infection-mediated interference of PPARγ-dependent pathways in adipocytes and other cells inside adipose depots such as macrophages is likely to create an altered local environment that, after antiretroviral treatment, leads to lipodystrophy in HIV-1-infected and HAART-treated patients

Secretory Proteome of Brown Adipocytes in Response to cAMP-Mediated Thermogenic Activation

Background: The secretory properties of brown adipose tissue are thought to contribute to the association between active brown fat and a healthy metabolic status. Although a few brown adipokines have been identified, a comprehensive knowledge of the brown adipose tissue secretome is lacking.Methods: Here, to examine the effects of thermogenic activation of brown adipocytes on protein secretion, we used isobaric tags for relative and absolute quantification (iTRAQ) analysis to determine how the secreted proteome of brown adipocytes (that detected in cell culture medium) differed in response to cAMP.Results: Our results indicated that 56 secreted proteins were up-regulated in response to cAMP. Of them, nearly half (29) corresponded to extracellular matrix components and regulators. Several previously known adipokines, were also detected. Unexpectedly, we also found five components of the complement system. Only 15 secreted proteins were down-regulated by cAMP; of them three were ECM-related and none was related to the complement system. We observed a partial concordance between the cAMP-regulated release of proteins (both from proteomics and from antibody-based quantification of specific proteins) and the cAMP-mediated regulation of their encoding transcript for the up-regulated secreted proteins. However, a stronger concordance was seen for the down-regulated secreted proteins.Conclusions: The present results highlight the need to investigate previously unrecognized processes such as the role of extracellular matrix in thermogenic activation-triggered brown fat remodeling, as well as the intriguing question of how brown adipocyte-secreted complement factors contribute to the signaling properties of active brown adipose tissue

A proof-of-concept superregenerative QPSK transceiver

In this paper we present a description and experimental verification of an HF-band proof-of-concept superregenerative transceiver for QPSK signals. We describe a simple implementation of an all-digital, FPGA-based, QPSK transmitter section. On the receiver side, the quench signal is generated in the same FPGA with a minimum of analog circuitry. As the main novelty, we present a simple synchronization scheme suitable for packetized transmissions.Peer ReviewedPostprint (author’s final draft

Passive acoustic monitoring for estimating human-wildlife conflicts: The case of bee-eaters and apiculture

In human-wildlife conflicts, it is crucial to develop accurate protocols for the reliable verification of the causative species and its relationship with potential damage claims. One of such conflicts is that occurring between apiarists and bee-eaters. In this work, we aim to assess the utility of passive acoustic monitoring (PAM) as an efficient methodology to measure European bee-eater (Merops apiaster) predation pressure at beehives and its impact on honeybees foraging activity. Using Autonomous Recording Units (ARUs) in apiaries, coupled to automated recognition methods for bee-eater calls identification, we found a positive relationship between Vocal Activity Rate (VAR) index and number of bee-eaters hunting attempts on honeybees. We also found that VAR varied over time, showing a lower predation pressure during midday hours and higher during the post-breeding migratory period. Honeybees flying activity was negatively associated with VAR and this relationship was conditioned by the hour of the day. Our study offers a new application of PAM and acoustic derived indices for the evaluation of potential damages caused by wildlife. We focused on the interaction between honeybees and the European bee-eater, but we expect PAM might be useful also to remotely monitor impacts to human activities produced by other vocally active species.European bee-eater monitoring was funded by the Department of Territory and Sustainability of the Generalitat de Catalunya. ARUs conception and design were partially supported by Programa de Investigación y Conservación del Zoo de Barcelona within the project ‘Nuevas tecnologías para viejos trabajos. Uso de grabadores automáticos para la detección y censo de especies raras y amenazadas. El caso de la alondra ricotí en Lleida y otras poblaciones pequeñas’. CPG acknowledges the support from Ministerio de Educación y Formación Profesional through the Beatriz Galindo Fellowship (Beatriz Galindo – Convocatoria 2020)

A Differential Pattern of Batokine Expression in Perivascular Adipose Tissue Depots From Mice

Depending on its anatomical placement, perivascular adipose tissue (PVAT) has been found to possess features more (e.g., aortic thoracic) or less (e.g., aortic abdominal) similar to brown/beige adipose tissue in mice, whereas PVAT surrounding the mesenteric arteries and the caudal part of abdominal aorta is similar to white fat. PVAT is thought to influence vascular function through the effects of adipose-secreted molecules on vessels. Brown adipose tissue was recently shown to play differential secretory role via secretion of the so-called batokines but the involvement of differential batokine production in PVAT brown/ beige plasticity was unclear. The current study characterizes for the first time the expression of batokines at aortic thoracic PVAT (tPVAT) and aortic abdominal PVAT (aPVAT) in comparison with typical brown and white adipose depots, in basal and thermogenically activated conditions. We found that both PVAT depots increased their expression of genes encoding the batokines bone morphogenetic protein-8b (BMP8B), fibroblast growth factor-21 (FGF21), and kininogen-2 (KNG2) in response to cold, indicating that, under cold-induced thermogenic activation, both thoracic aorta and abdominal aorta would experience intense local exposure to these PVAT-secreted batokines. In contrast, the gene expression levels of growth/differentiation factor-15 and vascular endothelial growth factor-A were induced only in tPVAT. Under short-term high-fat diet-induced thermogenic activation, the thoracic aorta would be specifically exposed to a local increase in PVAToriginating BMP8B, FGF21, and KNG2. Our data support the notion that acquisition of a brown/beige phenotype in PVAT is associated with upregulation of batokines, mainly BMP8B, FGF21, and KNG2, that can differentially target the vascular system

Signal and noise power spectra in superregenerative oscillators

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents a method to quantify noise in superregenerative oscillators. A frequency domain technique, originally intended to determine the signal response, can also be used to determine the noise response. This paper focuses on the procedure required to achieve this. Signal and noise spectra are obtained and their shape is compared. Finally, signal-to-noise ratio is computed for different quench signalsPeer ReviewedPostprint (author's final draft

Sub-nanosecond pulse filtering and amplification through firts-order controlled circuit instability

In this paper we investigate how to use controlled circuit instability in the filtering and amplification of narrow pulses. The basic circuit consists of a first-order RC network coupled to a negative resistance controlled by an external quench generator, which yields alternating periods of stability and instability. The study shows that when the circuit acts as a signal generator it can produce narrow exponential or Gaussian pulses, depending on the quench waveform applied. Included as a receiver front end, the circuit behaves as a highgain narrow-pulse filter. We also estimate the circuit parameters required to generate and receive sub-nanosecond pulses.Postprint (published version

A BPSK superregenerative receiver. Preliminary results

This paper describes a bit-synchronous superregenerative receiver suitable for BPSK demodulation. The output of the superregenerative oscillator (SRO), which reproduces the phase information of the input signal, is directly sampled by a D flip flop clocked by a signal derived from the quench waveform. Analytical background on the response of the SRO to a BPSK modulated input is presented. A PSpice macromodel of the receiver is also provided, allowing simulation in the linear and logarithmic modes of operation. Simulation results confirm the feasibility of the described approach. Finally, a proof-of-concept superregenerative receiver, capable of receiving a BPSK modulated carrier at 27 MHz with preliminary experimental results is presented. The measured sensitivity of this receiver is –99.5 dBm for a bit error rate of 10-3..Postprint (published version