684 research outputs found

    Tipificación en Gutierrezia (Asteraceae, Astereae)

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    During the course of the revision of the South American species of Gutierrezia, we have detected names that require typification. After the analysis of the protologues and the herbarium specimens, we designated eight lectotypes and one neotype for nine names of the Gutierrezia genus and we assigned the category of holotype to one specimen. A detailed discussion is provided for each case.Durante el transcurso de la revisión de las especies sudamericanas de Gutierrezia, hemos podido hallar nombres que requieren tipificación. Luego del análisis de los protologos y especímenes de herbario, hemos designado ocho lectótipos y un neótipo para nueve nombres del género Gutierrezia. Además, se asignó la categoría de hólotipo a un especimen. Se provee una discusión detallada para cada nombre

    Artificial insemination in South American camelids and wild equids

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    An overview of the present status of the use of artificial insemination (AI) in South American camelids and wild equids is offered. Technical aspects of semen collection, dilution and cryopreservation have limited the development and use of AI in camelid and equid species. To-date, efficiency is low but progress has been made and viable offspring have been produced through the use of AI in domestic South American camelids using both fresh and frozen semen. The origin, composition, and function of the viscous component of camelid seminal plasma remain a mystery and an obvious area for future research. A better understanding of the normal constituents of seminal plasma will enable the rational design of semen extenders suitable for camelids. Post-thaw sperm viability is very low, and studies are needed to address questions of optimal freezing and thawing procedures as well as the insemination dose. The basis for differences in reported pregnancy rates with sexed and frozen semen in domestic equids, and the ultimate success of AI in wild equids will require continued research into the ‘‘stallion effect’’, extenders and cryoprotectants, optimal volume and number of spermatozoa, temperatures during handling, processing an transport, and insemination techniques. In both camelids and equids, research on domestic species under controlled conditions provides and excellent opportunity to develop effective semen handling techniques for application in wild and endangered species of the respective families

    Neuro-hormonal effects of physical activity in the elderly.

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    Thanks to diagnostic and therapeutic advances, the elderly population is continuously increasing in the western countries. Accordingly, the prevalence of most chronic age-related diseases will increase considerably in the next decades, thus it will be necessary to implement effective preventive measures to face this epidemiological challenge. Among those, physical activity exerts a crucial role, since it has been proven to reduce the risk of cardiovascular diseases, diabetes, obesity, cognitive impairment and cancer. The favorable effects of exercise on cardiovascular homeostasis can be at least in part ascribed to the modulation of the neuro-hormonal systems implicated in cardiovascular pathophysiology. In the elderly, exercise has been shown to affect catecholamine secretion and biosynthesis, to positively modulate the renin-angiotensin-aldosterone system and to reduce the levels of plasma brain natriuretic peptides. Moreover, drugs modulating the neuro-hormonal systems may favorably affect physical capacity in the elderly. Thus, efforts should be made to actually make physical activity become part of the therapeutic tools in the elderly. © 2013 Femminella, de Lucia, Iacotucci, Formisano, Petraglia, Allocca, Ratto, DAmico, Rengo, Pagano, Bonaduce, Rengo and Ferrara

    Combining polynomial chaos expansions and genetic algorithm for the coupling of electrophysiological models

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    The number of computational models in cardiac research has grown over the last decades. Every year new models with di erent assumptions appear in the literature dealing with di erences in interspecies cardiac properties. Generally, these new models update the physiological knowledge using new equations which reect better the molecular basis of process. New equations require the fi tting of parameters to previously known experimental data or even, in some cases, simulated data. This work studies and proposes a new method of parameter adjustment based on Polynomial Chaos and Genetic Algorithm to nd the best values for the parameters upon changes in the formulation of ionic channels. It minimizes the search space and the computational cost combining it with a Sensitivity Analysis. We use the analysis of di ferent models of L-type calcium channels to see that by reducing the number of parameters, the quality of the Genetic Algorithm dramatically improves. In addition, we test whether the use of the Polynomial Chaos Expansions improves the process of the Genetic Algorithm search. We conclude that it reduces the Genetic Algorithm execution in an order of 103 times in the case studied here, maintaining the quality of the results. We conclude that polynomial chaos expansions can improve and reduce the cost of parameter adjustment in the development of new models.Peer ReviewedPostprint (author's final draft

    CYTOCHROME P450 3A13 AND ENDOTHELIN JOINTLY MEDIATE DUCTUS ARTERIOSUS CONSTRICTION TO OXYGEN IN MICE

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    The fetal ductus arteriosus (DA) contracts to oxygen, and this feature, maturing through gestation, is considered important for its closure at birth. We have previously obtained evidence of the involvement of cytochrome P-450, possibly of the 3A subfamily (CYP3A), in oxygen sensing and have also identified endothelin (ET)-1 as the attendant effector for the contraction. Here, we examined comparatively wild-type (WT) and CYP3Anull (Cyp3a(-/-)) mice for direct validation of this concept. We found that the CYP3A subfamily is represented only by CYP3A13 in the WT DA. CYP3A13 was also detected in the DA by immunofluorescence microscopy, being primarily colocalized with the endoplasmic reticulum in both endothelial and muscle cells. However, a distinct signal was also evident in the plasma membrane. Isolated DAs from term WT animals developed a sustained contraction to oxygen with transient contractions superimposed. Conversely, no tonic response occurred in Cyp3a(-/-) DAs, whereas the phasic response persisted unabated. Oxygen did not contract the preterm WT DA but caused a full-fledged contraction after retinoic acid (RA) treatment. RA also promoted an oxygen contraction in the Cyp3a(-/-) DA. However, responses of RA-treated WT and Cyp3a(-/-) mice differed in that only the former abated with ET-1 suppression. This implies the existence of an alternative target for RA responsible for the oxygen-induced contraction in the absence of CYP3A13. In vivo, the DA was constricted in WT and Cyp3a(-/-) newborns, although with a tendency to be less narrowed in the mutant. We conclude that oxygen acts primarily through the complex CYP3A13 (sensor)/ET-1 (effector) and, in an accessory way, directly onto ET-1. However, even in the absence of CYP3A13, the DA may close postnatally thanks to the contribution of ET-1 and the likely involvement of compensating mechanism(s) identifiable with an alternative oxygen-sensing system and/or the withdrawal of relaxing influence(s) operating prenatally

    Microbubble PhoXonic resonators: Chaos transition and transfer

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    We report the activation of optomechanical chaotic oscillations in microbubble resonators (MBRs) through a blue-side excitation of its optical resonances. We confirm the sequence of quasi-periodical oscillation, spectral continuum and aperiodic motion; as well as the transition to chaos without external feedback or modulation of the laser source. In particular, quasi periodic transitions and a spectral continuum are reported for MBRs with diameters up to 600 μm, whereas only an abrupt transition into a spectral con- tinuum is observed for larger microbubbles

    Contemporary surgical practice in the management of anal fistula: results from an international survey

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    Background Management of anal fistula (AF) remains challenging with many controversies. The purpose of this study was to explore current surgical practice in the management of AF with a focus on technical variations among surgeons. Methods An online survey was conducted by inviting all surgeons and physicians on the membership directory of European Society of Coloproctology and American Society of Colon and Rectal Surgeons. An invitation was extended to others via social media. The survey had 74 questions exploring diagnostic and surgical techniques. Results In March 2018, 3572 physicians on membership directory were invited to take part in the study 510 of whom (14%) responded to the survey. Of these respondents, 492 (96%) were surgeons. Respondents were mostly colorectal surgeons (84%) at consultant level (84%), age ≥ 40 years (64%), practicing in academic (53%) or teaching (30%) hospitals, from the USA (36%) and Europe (34%). About 80% considered fistulotomy as the gold standard treatment for simple fistulas. Endorectal advancement flap was performed using partial- (42%) or full-thickness (44%) flaps. Up to 38% of surgeons performed ligation of the intersphincteric fistula tract (LIFT) sometimes with technical variations. Geographic and demographic differences were found in both the diagnostic and therapeutic approaches to AF. Declared rates of recurrence and fecal incontinence with these techniques were variable and did not correlate with surgeons’ experience. Only 1–4% of surgeons were confident in performing the most novel sphincter-preserving techniques in patients with Crohn’s disease. Conclusions Profound technical variations exist in surgical management of AF, making it difficult to reproduce and compare treatment outcomes among different centers

    Nonlinear optical effects and optomechanical oscillations in hollow Whispering Gallery Mode microresonators: coexistence, suppression, amplification and route to chaos

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    Whispering Gallery Mode (WGM) hollow microcavities turn out to be the site of an extremely rich and complex phenomenological scenario when pumped with a continuous-wave laser source. The coexistence of numerous non-linear and optomechanical effects have been reviewed in this paper. In our previous works we have investigated and described non-linear emissions as the stimulated Brillouin and Raman scattering, the degenerated and non-degenerated Kerr effects, such as four wave mixing (FWM). These effects happened concomitantly to parametric optomechanical oscillations which are the consequence of the radiation pressure. We have confirmed the regenerative oscillation of acoustic eigenmodes of the cavity leading to parametric instabilities and the activation of optomechanical chaotic oscillations. Finally, we have demonstrated that the blue-side excitation of WGM resonances lead to the chaos transition with a spectral evolution depending on the cavity size
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