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

Testicular spermatozoa and male germ cells evolution in "Dina lineata" (Hirudinea: Erpobdellidae) studied by scanning electron microscopy

A Dina lineata, hirudini erpobdèllid amb fecundació traumàtica hipodèrmica, cada espermatogònia primitiva, lliure en els sacs testiculars, entra en un procés de set divisions mitòtiques anticlinals cariocinètiques i no citocinètiques per formar poliplasts amb 2, 4, 8, 16, 32, 64 espermatogònies i, finalment, 128 espermatòcits primaris. Les cel•lules, en un mateix poliplast, evolucionen sincrònicament lligades per un pont a una massa citoplasmàtica central comuna anomenada citòfor. Una darrera divisió, meiòtica, porta a un poliplast amb 512 espermàtides. Per un complex procés morfogenètic de diferenciació cel•lular, cada espermàtida, arrodonida i d'uns 1,3 µm de diàmetre, esdevé un espermatozoide filamentós i helicoïdal d'uns 48 µm de longitud per 0,3 µm de diàmetre. L'ordre cronològic de diferenciació de les diverses regions del gàmeta és el següent: elongació del flagel, elongació i espiralització del nucli, elongació de la regió mitocondrial i elongació i espiralització, primer de l'acrosoma posterior i, després, de l'acrosoma anterior. A l'espermatozoide: 1) L'acrosoma posterior (7 µm) és una doble hèlix dextrògira formada per dues fibres, una d'estreta i una altra d'ampla, que descriuen, cadascuna, set voltes completes. 2) L'acrosoma anterior (6,5 µm) és un eix a l'entorn del qual una mateixa expansió cintiforme descriu, en sentit dextrògir, set voltes completes. 3) La regió nuclear (5,5 µm) és també una doble hèlix dextrògira integrada per dues fibres. A la base presenten el mateix gruix, però, a mesura que se n'allunyen, l'alteren a voltes alternes. 4) Les regions mitocondrial (8,5 µm) i flagellar (20 µm) són externament llises.This paper studies the male germ cells evolution in the leech Dina lineata by scanning electron microscopy. A primitive spermatogonium is an oval cell measuring 1,6 per 6 µm. Seven not-finished consecutive anticlinal mitotic divisions lead to the formation of isogenic groups with 2, 4, 8, 16, 32, 64 spermatogonia and, finally, 128 primary spermatocytes. The cells are all clustered in only one group and they evolve gradually and synchronically, remaining connected by cytoplasmic bridges to a central cytoplasmic mass called cytophore. A last division, which is meiotic, gives rise to an isogenic group with 512 spermatids: the cellular body of each one is reduced to 1,3 µm in diameter. By means of a complex spermiogenic process of cellular differentiation, each body becomes a filiform and helicoid spermatozoon measuring 48 µm in length and 0.3 µm in diameter. The morphogenetic and chronologic sequence of the various regions is the following: flagellum elongation; nucleus spiralization and elongation; mitochondrial region elongation; and finally, spiralization and elongation, first of the posterior acrosome and after of the anterior acrosome. In the spermatozoon: 1) The posterior acrosome (7 µm) is a right-handed double helix integrated by two fibers: a narrow one and a wide one; each describes seven complete turns. 2) The anterior acrosome (6.5 µm) is a longitudinal axis which has a ribbonshaped expansion describing seven right-handed complete turns around the same axis. 3) The nuclear region (5.5 µm) is also a right-handed double helix integrated by two fibers. On their base they show the same trickness, but this is alternatively altered along it from the base to the other side. 4) The mitochondrial region (8.5 µm) and the flagellar one (20 µm) are externally smooth

Resveratrol metabolite profiling in clinical nutrition research-from diet to uncovering disease risk biomarkers: epidemiological evidence

Resveratrol is a bioactive plant compound that has drawn scientific and media attention owing to its protective effects against a wide variety of illnesses, including cardiovascular diseases and cancer. In the last two decades, a plethora of preclinical studies have shown these beneficial effects, and some of them have been supported by clinical trials. However, there are few epidemiological studies assessing these relationships, showing mostly inconsistent results among them. This could be partially due to the difficulty of accurately estimating dietary resveratrol exposure. The development of Phenol-Explorer, a database containing resveratrol food-composition data, will facilitate the estimation of resveratrol intake. Moreover, the discovery and validation of a nutritional biomarker of this exposure, urinary resveratrol metabolite profile, will allow a more accurate assessment of dietary resveratrol exposure. Few epidemiological studies have assessed the potential health effects of resveratrol. Resveratrol was not associated with total mortality, cancer, or cardiovascular events, but it was associated with an improvement of serum glucose and triglyceride levels and a decrease in heart rate. Together, these findings suggest a potential cardioprotective effect of resveratrol in epidemiological studies, although the evidence is still scarce

Espacios híbridos, espacios humanos, para un futuro “viable”: revisitando la psicología ambiental

Llibre d'actes: Congrés Internacional de Psicologia Ambiental, que inclou el XII Congrés de Psicologia Ambiental (PsicAmb) i les VI Jornades Científiques de l'ArpEnv. Barcelona, 22-25 octubre 2013.Este libro es una recopilación de los trabajos presentados en el Congreso Internacional de Psicología ambiental “Espacios híbridos, espacios humanos, para un futuro “viable”: revisitando la Psicología ambiental”, celebrado en Barcelona los días 22 a 25 de octubre de 2013. En este encuentro se hizo coincidir el XII Congreso de Psicología de Psicamb (asociación que reúne la Psicología ambiental desarrollada en la Península Ibérica y las islas Canarias y Baleares) con las 6as jornadas científicas del ArpEnv (asociación de Psicología ambiental de la área francófona europea), además de estar abierto a las aportaciones de otros colegas de todo el mundo

Low levels of a urinary biomarker of dietary polyphenol are associated with substantial cognition decline over a three-year period in older adults: the Invecchiare in Chianti (InCHIANTI) Study.

Objectives: To investigate the association of total urinary polyphenols (TUP) and total dietary polyphenols (TDP) with cognitive decline in an older population. Design: The Invecchiare in Chianti (InCHIANTI) study, a cohort study with a 3-year of follow-up. Setting: tuscany, italy. Participants: Non-demented adults aged 65 and older (N=652). Measurements: TUP and TDP concentrations were analysed at baseline using the Folin-Ciocalteu assay and a validated food frequency questionnaire, respectively. Cognition was assessed using the Mini-Mental State Examination (MMSE) and Trail Making Test (TMT) at baseline and after three years of follow-up. A substantial cognitive decline was defined as a reduction in the MMSE score of 3 or more points and as an increase of at least 29 seconds on the TMT A and 68 seconds on the TMT B (these thresholds represent the worst 10% of the distribution of decline) or as test discontinued due to multiple mistakes in TMT A and B at follow-up. Results: Higher TUP levels were associated with lower risk of substantial cognitive decline on the MMSE (odds ratio [OR] comparing extreme tertiles = 0.53; 95% confidence interval [CI] = 0.340.85; P-trend = 0.008) and on the TMT-A (OR = 0.52; 95 % CI = 0.280.96; P-trend = 0.03), but not on TMT-B in a logistic regression model that adjusted for baseline cognitive score and potential confounding factors. TDP did not affect the developing substantial cognitive decline in both tests. Conclusion: High concentrations of polyphenols, a nutritional biomarker of polyphenol intake, were associated with a lower risk of substantial cognitive decline in the older population studied over a three-year period, suggesting a protective effect against cognitive impairment

A computational framework for polyconvex large strain elasticity for geometrically exact beam theory

In this paper, a new computational framework is presented for the analysis of nonlinear beam finite elements subjected to large strains. Specifically, the methodology recently introduced in Bonet et al. (Comput Methods Appl Mech Eng 283:1061–1094, 2015) in the context of three dimensional polyconvex elasticity is extended to the geometrically exact beam model of Simo (Comput Methods Appl Mech Eng 49:55–70, 1985), the starting point of so many other finite element beam type formulations. This new variational framework can be viewed as a continuum degenerate formulation which, moreover, is enhanced by three key novelties. First, in order to facilitate the implementation of the sophisticated polyconvex constitutive laws particularly associated with beams undergoing large strains, a novel tensor cross product algebra by Bonet et al. (Comput Methods Appl Mech Eng 283:1061–1094, 2015) is adopted, leading to an elegant and physically meaningful representation of an otherwise complex computational framework. Second, the paper shows how the novel algebra facilitates the re-expression of any invariant of the deformation gradient, its cofactor and its determinant in terms of the classical beam strain measures. The latter being very useful whenever a classical beam implementation is preferred. This is particularised for the case of a Mooney–Rivlin model although the technique can be straightforwardly generalised to other more complex isotropic and anisotropic polyconvex models. Third, the connection between the two most accepted restrictions for the definition of constitutive models in three dimensional elasticity and beams is shown, bridging the gap between the continuum and its degenerate beam description. This is carried out via a novel insightful representation of the tangent operator