1,173 research outputs found
Leptin, a railroad switch enabling crossover signals among inflammation, immunity and metabolism
White adipose tissue is currently considered as an active endocrine organ that secretes a plethora of factors named adipokines, some of them being of pro-inflammatory nature that likely contribute to the low-level systemic inflammation, a status that is often present in metabolic syndrome-associated chronic pathologies such as obesity, type 2 diabetes, and atherosclerosis. Leptin is historically indisputably one of the most important adipokine secreted by fat cells, with a variety of physiological roles ranging from to the control of metabolism, energy homeostasis and inflammatory response to cognition. Leptin is also implicated in the connection between nutritional status and immune competence, modulating both the innate and adaptive immune responses in normal as well as pathological conditions. It has been shown that conditions characterized by low leptin levels are associated with increased infection susceptibility. Conversely, immune-mediated disorders such as autoimmune diseases are associated with increased secretion of leptin and production of proinflammatory cytokines. Thus, leptin can be easily considered as a frank mediator of metabolic and inflammatory/immune responses.Adipobiology 2010; 2: 33-40
Quasi-Exact Solvability and the direct approach to invariant subspaces
We propose a more direct approach to constructing differential operators that
preserve polynomial subspaces than the one based on considering elements of the
enveloping algebra of sl(2). This approach is used here to construct new
exactly solvable and quasi-exactly solvable quantum Hamiltonians on the line
which are not Lie-algebraic. It is also applied to generate potentials with
multiple algebraic sectors. We discuss two illustrative examples of these two
applications: an interesting generalization of the Lam\'e potential which
posses four algebraic sectors, and a quasi-exactly solvable deformation of the
Morse potential which is not Lie-algebraic.Comment: 17 pages, 3 figure
FSR19 and FSR25 confirmed as two new faint and metal-rich globular clusters in the galactic bulge
We combined the near-IR photometry from the VISTA Variables in the Vía Láctea extended Survey (VVVX) with Gaia EDR3 catalog to study some properties of FSR19 and FSR25. These are confirmed to be low luminosity metal-rich bulge globular clusters (Obasi et al. 2020). The proper motions (PM) remain unchanged and the Color magnitude diagrams (CMD) are consistent with what we previously reported and the red giant branches are narrower than the field
Solar and biomass hybridization through hydrothermal carbonization
Hydrothermal carbonization process can transform wet bio-wastes into value-added products. This work aims to hybridize a concentrating solar technology and a biomass reactor for the continuous and sustainable valorization of biomass. The novel technology proposed integrates a linear beam-down solar field with a twin-screw reactor for continuous HTC process. The solar field consists of two reflections that concentrate linearly the sun energy on the ground, where the twin-screw reactor is placed. A mathematical model is proposed to solve both the heat transfer and HTC kinetics for a co-rotating twin-screw reactor. The incoming heat flux from the solar field (8-20 kW/m(2)), the reactor length (L/D = 30-60 where D is the diameter) and the rotating velocity of the screw (25-100 rpm) are the main variables used to process the biomass up to the desired severity factor. The simulation results of different lignocellulosic biomasses (loblolly pine, sugarcane bagasse, corn stover and rice husk) are validated against literature data. The developed model shows good agreement with experimental results shown in the literature. The proposed technology foresees hydrochar yields of 64-78% for severity factors of 4.2 and 5.3, respectively, in agreement to the experimental results of 63-70% shown in literature. (C) 2021 Elsevier Ltd. All rights reserved
Phenotypic gender in Hormathophylla spinosa (Brassicaceae), a perfect hermaphrodite with tetradynamous flowers, is variable
Abstract. Angiosperms show an evolutionary trend from an indefinite to a fixed number of floral organs. When floral formula inconstancy in recent angiosperms is reported, it is often considered as a byproduct of stress and its fitness consequences remain mostly unexplored. We report substantial nonhomeotic meristic variation in stamen number (0-10 stamens per flower) in two populations of Hormathophylla spinosa during four years. This variation was plastic, suggesting its functional role in the adjustment of phenotypic gender. However, no correlations were found between phenotypic gender and plant size, pollinator or herbivore abundance. Effects on female reproductive success were inconsistent on a per-flower and on a perplant basis, rendering adaptive explanations in terms of selfing or resource adjustment unsatisfactory with the data available. Nevertheless, individuals showing larger interannual variation in phenotypic gender showed higher female reproductive success, suggesting an advantage for gender modification. Although our results do not easily conform to any adaptive explanation, this remarkable example of breakdown of trait canalization should stimulate the study of the mechanisms and ultimate causes responsible for the maintenance of fixed floral traits
Social media in cardiology: Reasons to learn how to use it
Social media has changed the way we learn, educate, and interact with our peers. The dynamic nature of social media and their immediate availability through our portable devices (smartphones, tablets, smartwatches, etc.) is quickly transforming the way we participate in society. The scope of these digital tools is broad as they deal with many different aspects: Teaching and learning, case discussion, congresses coverage, peer to peer interaction, research are examples worth mentioning. The scientific societies considered more innovative, are promoting these tools between their members. These new concepts need to be known by the cardiologists to stay updated, as countless information is moving rapidly through these channels. We summarize the main reasons why learning how to use these tools to be part of the conversation is essential for the cardiologist in training or fully stablished
Boundary conditions for hyperbolic formulations of the Einstein equations
In regards to the initial-boundary value problem of the Einstein equations,
we argue that the projection of the Einstein equations along the normal to the
boundary yields necessary and appropriate boundary conditions for a wide class
of equivalent formulations. We explicitly show that this is so for the
Einstein-Christoffel formulation of the Einstein equations in the case of
spherical symmetry.Comment: 15 pages; text added and typesetting errors corrected; to appear in
Classical and Quantum Gravit
Correlation between microstructure and electric properties in SnO(2) rich enamels
No abstract availabl
Analysis of the “Plan Fronteras” for Clean Cooking in Ecuador
The aim of this research is to analyze the introduction of the “Plan Fronteras” in Ecuador. The Plan Fronteras analyses the effects of introducing induction stoves in terms of electricity demand, energy consumption and greenhouse gas emissions, previous to the implementation of the National efficient cooking program, which is the first program of widespread access to clean cooking alternatives, which aims to introduce 3 million of induction stoves in the country. The impact of the induction stoves on Ecuador electric network has been analyzed by measuring electric grid parameters, energy and power consumption. The results of the study show that the electric grid parameters are within the permitted levels of the regulation of the country. Further on, a coincidence factor of 0.16 for induction stoves utilization has been registered when it was found. An estimation of the electric demand has been identified when implementing the National efficient cooking program with this value. The results of the study show that when analyzing the highlands and coastal regions at the same time, the peak demand in the country occurs at 19:00, whit a power requirement of 2860 MW. Finally, a study on energy demand and LPG savings after the implementation of the National efficient cooking program has been accomplished. The study has been evaluated and compared with future business as usual scenarios and new policies from 2016 until 2032. The results of the comparison reveal a reduction of the energy demand of 20 million GJ in 2032, and a reduction of 40.8 million tons of greenhouse gas emissions, between 2016 and 2032.
Keywords: Household survey, clean cooking, acces to electricy, induction stoves, cooking fuel.
JEL Classifications: L94, R52, Q
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