3,558 research outputs found
Los hongos comestibles silvestres, su contexto alimentario propuesta de desidratado como proceso agroindustrial
TESIS PARA OBTENER EL GRADO DE MAESTRO EN AGROINDUSTRIA RURAL, DESARROLLO TERRITORIAL Y TURISMO AGROALIMENTARIO OTORGADOR POR EL INSTITUTO DE CIENCIAS AGROPECUARIAS Y RURALES (ICAR) UAEMEste texto trata sobre una propuesta de agroindustria rural de productos deshidratados de hongos comestibles silvestres (HCS), sustentando su importancia como productos alimentarios diferenciados, y cuyo proceso intermedio de transformación puede contrarrestar la fuga de valor territorial al que actualmente están sujetos, con la intención de contribuir al desarrollo local. A lo largo del documento, se describe parte del contexto alimentario de los HCS, el cual, presenta realidades matizadas que se adscriben a lo singular de cada territorio, con el común denominador de ser visualizados como alimentos únicos, gracias a su carácter natural, trascendencia cultural y tipicidad organoléptica. Esto se realiza con la intención de ampliar las referencias y las reflexiones acerca de los fenómenos de recolección y consumo de los mismos en espacios rurales forestales, información que muchas veces es limitada
High precision abundances in the 16 Cyg binary system: a signature of the rocky core in the giant planet
We study the stars of the binary system 16 Cygni to determine with high
precision their chemical composition. Knowing that the component B has a
detected planet of at least 1.5 Jupiter masses, we investigate if there are
chemical peculiarities that could be attributed to planet formation around this
star. We perform a differential abundance analysis using high resolution (R =
81,000) and high S/N (~700) CFHT/ESPaDOnS spectra of the 16 Cygni stars and the
Sun; the latter was obtained from light reflected of asteroids. We determine
differential abundances of the binary components relative to the Sun and
between components A and B as well. We achieve a precision of about 0.005 dex
and a total error ~0.01 dex for most elements. The effective temperatures and
surface gravities found for 16 Cyg A and B are Teff = 5830+/-7 K, log g =
4.30+/-0.02 dex, and Teff = 5751+/-6 K, log g = 4.35+/-0.02 dex, respectively.
The component 16 Cyg A has a metallicity ([Fe/H]) higher by 0.047+/-0.005 dex
than 16 Cyg B, as well as a microturbulence velocity higher by 0.08 km/s. All
elements show abundance differences between the binary components, but while
the volatile difference is about 0.03 dex, the refractories differ by more and
show a trend with condensation temperature, which could be interpreted as the
signature of the rocky accretion core of the giant planet 16 Cyg Bb. We
estimate a mass of about 1.5-6 M_Earth for this rocky core, in good agreement
with estimates of Jupiter's core.Comment: ApJ Letters. Press release: http://cfht.hawaii.edu/en/news/16CygAB
Mathematical Modeling of Immune Responses to Hepatitis C Virus Infection
An existing mathematical model of ordinary differential equations was studied to better understand the interactions between hepatitis C virus (HCV) and the immune system cells in the human body. Three possible qualitative scenarios were explored: dominant CTL response, dominant antibody response, and coexistence. Additionally, a sensitivity analysis was carried out to rank model parameters for each of these scenarios. Therapy was addressed as an optimal control problem. Numerical solutions of optimal controls were computed using a forward-backward sweep scheme for each scenario. Model parameters were estimated using ordinary least squares fitting from longitudinal data (serum HCV RNA measurements) given in reported literature
Mathematical modeling of energy consumption in the acute inflammatory response
When a pathogen invades the body, an acute inflammatory response is activated to eliminate the intruder. In some patients, runaway activation of the immune system may lead to collateral tissue damage and, in the extreme, organ failure and death.
Experimental studies have found an association between severe infections and depletion in levels of adenosine triphosphate (ATP), increase in nitric oxide production, and accumulation of lactate, suggesting that tissue energetics is compromised.
We present a computational model consisting of ordinary differential equations to explore the dynamics of the acute inflammatory response against infections caused when a pathogen makes its way into a host. This model incorporates energy production along with the energy requirements that arise when fighting such an infection. In particular, we investigate the role of energetics during infection and explore the relation between overproduction of nitric oxide (NO), lactate, altered adenosine triphosphate (ATP) levels, and sepsis.
Finally, a data-driven approach is used to extend our model as an effort to better understand the role of energy in sepsis. This extended model is calibrated by fitting animal data from a study done in thirty-two baboons that were induced into sepsis after infusing E. coli intravenously. Using Bayesian analysis, we quantify uncertainty in model parameters and with them we investigate differences across different populations, including survivors and non-survivors
Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion
We present NLTE Li abundances for 88 stars in the metallicity range -3.5 <
[Fe/H] < -1.0. The effective temperatures are based on the infrared flux method
with improved E(B-V) values obtained mostly from interstellar NaI D lines. The
Li abundances were derived through MARCS models and high-quality UVES+VLT,
HIRES+Keck and FIES+NOT spectra, and complemented with reliable equivalent
widths from the literature. The less-depleted stars with [Fe/H] < -2.5 and
[Fe/H] > -2.5 fall into two well-defined plateaus of A_{Li} = 2.18 (sigma =
0.04) and A_{Li} = 2.27 (sigma = 0.05), respectively. We show that the two
plateaus are flat, unlike previous claims for a steep monotonic decrease in Li
abundances with decreasing metallicities. At all metallicities we uncover a
fine-structure in the Li abundances of Spite plateau stars, which we trace to
Li depletion that depends on both metallicity and mass. Models including atomic
diffusion and turbulent mixing seem to reproduce the observed Li depletion
assuming a primordial Li abundance A_{Li} = 2.64, which agrees well with
current predictions (A_{Li} = 2.72) from standard Big Bang nucleosynthesis.
Adopting the Kurucz overshooting model atmospheres increases the Li abundance
by +0.08 dex to A_{Li} = 2.72, which perfectly agrees with BBN+WMAP.Comment: A&A Letters, in pres
Diseño de un controlador de seguimiento para un sistema SISO de servoposicionamiento neumático
Pneumatic systems have many advantages, such as simplicity, reliability, low-cost, long life, etc. making them attractive for rapid development and widespread application, but the complexity of the airflow through the valve port and the friction between the cylinder and piston make it difficult to establish an exact mathematical model and control the pneumatic system with high precision. Experiments were conducted with a 25 mm bore rod-less pneumatic cylinder and a 5/3 way proportional control valve. In this contribution, I propose a nonlinear robust tracking control strategy to solve the tracking problem of the servo pneumatic positioning system. The approach is novel in the sense that it takes into account the nonlinearities inherent to pneumatic servo positioning systems and considers position, velocity and pressure difference in the chambers of the pneumatic cylinder as feedback states. The suggested control strategy is implemented in simulation and on the real system. Experimental results from an implementation on a test ring show a high position tracking control performance.Los sistemas neumáticos tienen varias ventajas que permitieron su rápido desarrollo y uso generalizado, tales como: simplicidad, confiabilidad, bajo costo, larga vida etc. Sin embargo, la complejidad del flujo de aire a través de los orificios de la válvula y la naturaleza de la fuerza de fricción entre las paredes del cilindro y el pistón, dificultan la obtención de modelos matemáticos exactos y el control de los sistemas neumáticos con alta precisión. Experimentos fueron llevados a cabo con un cilindro sin vástago de 25 mm de diámetro y una válvula de control proporcional de 5 puertos -3 vías. En este artículo, proponemos una estrategia de control de posicionamiento robusta para solucionar el problema de un sistema de servo posicionamiento neumático. El enfoque es novedoso en el sentido de que tiene en cuenta las no linealidades inherentes a los sistemas de servo posicionamiento neumático y considera posición, velocidad y diferencia de presiones en las cámaras del cilindro neumático como estados de retroalimentación. La estrategia de control propuesta es implementada en simulación y sobre el sistema real. Los resultados experimentales de la implementación de la estrategia en el sistema de servo-posicionamiento neumático muestran un alto desempeño en el control de seguimiento de posición
Research and Formative Action on the Effects of Self-Control on Stress and Decision-Making in People with Eating Disorders
Previous research has shown deficits in stress management and decision-making in teen college girls with Eating Disorders (ED). The aim of this research is to relate the impact of self-control on stress and decision-making in this population group in order to design an educational and training project to reduce these difficulties. For this purpose, qualitative research was carried out by means of semi-structured interviews with adolescent patients suffering from ED between 18 and 22 years of age and with various specialists in the mentioned disorder. The interviews were analysed from a quantitative and qualitative perspective using MAXQDA software. The results show that a lack of adaptive self-control can both directly and indirectly affect stress management and decision-making. Meanwhile, demanding self-control or, conversely, impulsive behaviours, tend to increase the problems in the variables studied. On the other hand, the academic field as well as social and family relationships should be mentioned as possible negative elements that interfere with stress management and decision-making. Finally, the creation of specific educational projects on self-control could improve variables such as stress management and decision-making in this population group. To achieve these objectives, training for the education community and clinicians would also be beneficial
2MASS J18082002-5104378: The brightest (V=11.9) ultra metal-poor star
Context. The most primitive metal-poor stars are important for studying the
conditions of the early galaxy and are also relevant to big bang
nucleosynthesis. Aims. Our objective is to find the brightest (V<14) most
metal-poor stars. Methods. Candidates were selected using a new method, which
is based on the mismatch between spectral types derived from colors and
observed spectral types. They were observed first at low resolution with EFOSC2
at the NTT/ESO to obtain an initial set of stellar parameters. The most
promising candidate, 2MASS J18082002-5104378 (V=11.9), was observed at high
resolution (R=50 000) with UVES at the VLT/ESO, and a standard abundance
analysis was performed. Results. We found that 2MASS J18082002-5104378 is an
ultra metal-poor star with stellar parameters Teff = 5440 K, log g = 3.0 dex,
vt = 1.5 km/s, [Fe/H] = -4.1 dex. The star has [C/Fe]<+0.9 in a 1D analysis, or
[C/Fe]<=+0.5 if 3D effects are considered; its abundance pattern is typical of
normal (non-CEMP) ultra metal-poor stars. Interestingly, the star has a binary
companion. Conclusions. 2MASS J1808-5104 is the brightest (V=11.9) metal-poor
star of its category, and it could be studied further with even higher S/N
spectroscopy to determine additional chemical abundances, thus providing
important constraints to the early chemical evolution of our Galaxy.Comment: A&A Letter
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