2,700 research outputs found
An Estimated New-Keynesian Model with Unemployment as Excess Supply of Labor
Wage stickiness is incorporated to a New-Keynesian model with variable capital in a
way that generates endogenous unemployment fluctuations as the log difference
between aggregate labor supply and aggregate labor demand. After estimation with U.S.
data, the implied second-moment statistics of the unemployment rate provide a
reasonable match with those observed in the data. Our results also show that wagepush
shocks, demand shifts and monetary policy shocks are the three major
determinants of unemployment fluctuations. Compared to an estimated canonical DSGE
model without unemployment: wage stickiness is higher, labor supply elasticity is lower,
the slope of the New-Keynesian Phillips curve is flatter, and the importance of
technology innovations on output growth variability increases
Epidemic Incidence in Correlated Complex Networks
We introduce a numerical method to solve epidemic models on the underlying
topology of complex networks. The approach exploits the mean-field like rate
equations describing the system and allows to work with very large system
sizes, where Monte Carlo simulations are useless due to memory needs. We then
study the SIR epidemiological model on assortative networks, providing
numerical evidence of the absence of epidemic thresholds. Besides, the time
profiles of the populations are analyzed. Finally, we stress that the present
method would allow to solve arbitrary epidemic-like models provided that they
can be described by mean-field rate equations.Comment: 5 pages, 4 figures. Final version published in PR
Synchronization of Kuramoto Oscillators in Scale-Free Networks
In this work, we study the synchronization of coupled phase oscillators on
the underlying topology of scale-free networks. In particular, we assume that
each network's component is an oscillator and that each interacts with the
others following the Kuramoto model. We then study the onset of global phase
synchronization and fully characterize the system's dynamics. We also found
that the resynchronization time of a perturbed node decays as a power law of
its connectivity, providing a simple analytical explanation to this interesting
behavior.Comment: 7 pages and 4 eps figures, the text has been slightly modified and
new references have been included. Final version to appear in Europhysics
Letter
Technological properties of maize tortillas produced by microwave nixtamalization with variable alkalinity
This research was conducted to determine the quality, physicochemical, textural, compositional, nutritional, viscoamylographic and sensory properties of maize tortillas produced with a Modified tortilla-making process (MTMP) of variable alkalinity (0.125, 0.25 and 0.5% Ca(OH)2 w/w) and compared to the commercial brand MASECA ®. In general, tortillas from MTMP showed higher pH, total color difference (ΔE), tensile strength/cutting force, protein, lipids, crude fibre, lysine, tryptophan, in vitro protein digestibility and lower Hunter L value, loss of weight during cooking and moisture content than MASECA® tortillas. No significant differences were found in the sensory analysis of 22 descriptors of tortillas made from MASECA® and MTMP with Ca(OH)2 concentrations of 0.125 and 0.25% (w/w). However, panelist identified principal effects on changes in four attributes (aroma, appearance, flavor, and after taste flavor) and seven descriptors in tortillas from MTMP prepared with the maximum lime concentration (0.5% w/w). Microwave nixtamalization produce tortillas with acceptable physicochemical, textural, quality, compositional/nutritional and pasting properties.Key words: Maize, modified nixtamalization, tortillas, technological properties
Critical load and congestion instabilities in scale-free networks
We study the tolerance to congestion failures in communication networks with
scale-free topology. The traffic load carried by each damaged element in the
network must be partly or totally redistributed among the remaining elements.
Overloaded elements might fail on their turn, triggering the occurrence of
failure cascades able to isolate large parts of the network. We find a critical
traffic load above which the probability of massive traffic congestions
destroying the network communication capabilities is finite.Comment: 4 pages, 3 figure
Local versus Global Knowledge in the Barabasi-Albert scale-free network model
The scale-free model of Barabasi and Albert gave rise to a burst of activity
in the field of complex networks. In this paper, we revisit one of the main
assumptions of the model, the preferential attachment rule. We study a model in
which the PA rule is applied to a neighborhood of newly created nodes and thus
no global knowledge of the network is assumed. We numerically show that global
properties of the BA model such as the connectivity distribution and the
average shortest path length are quite robust when there is some degree of
local knowledge. In contrast, other properties such as the clustering
coefficient and degree-degree correlations differ and approach the values
measured for real-world networks.Comment: Revtex format. Final version appeared in PR
Caveolin-1 Modulates Mechanotransduction Responses to Substrate Stiffness through Actin-Dependent Control of YAP
The transcriptional regulator YAP orchestrates many cellular functions, including tissue homeostasis, organ growth control, and tumorigenesis. Mechanical stimuli are a key input to YAP activity, but the mechanisms controlling this regulation remain largely uncharacterized. We show that CAV1 positively modulates the YAP mechanoresponse to substrate stiffness through actin-cytoskeleton-dependent and Hippo-kinase-independent mechanisms. RHO activity is necessary, but not sufficient, for CAV1-dependent mechanoregulation of YAP activity. Systematic quantitative interactomic studies and image-based small interfering RNA (siRNA) screens provide evidence that this actin-dependent regulation is determined by YAP interaction with the 14-3-3 protein YWHAH. Constitutive YAP activation rescued phenotypes associated with CAV1 loss, including defective extracellular matrix (ECM) remodeling. CAV1-mediated control of YAP activity was validated in vivo in a model of pancreatitis-driven acinar-to-ductal metaplasia. We propose that this CAV1-YAP mechanotransduction system controls a significant share of cell programs linked to these two pivotal regulators, with potentially broad physiological and pathological implications. Moreno-Vicente et al. report that CAV1, a key component of PM mechanosensing caveolae, mediates adaptation to ECM rigidity by modulating YAP activity through the control of actin dynamics and phosphorylation-dependent interaction of YAP with the 14-3-3-domain protein YWHAH. Cav1-dependent YAP regulation drives two pathophysiological processes: ECM remodeling and pancreatic ADM. © 2018 The Author
Microgrids Power Quality Enhancement Using Model Predictive Control
In electric power systems, any deviation with respect to the theoretical sinusoidal waveform is considered to be a disturbance in the power quality of the electrical grid. The deviation can alter any of the parameters of the waveform: frequency, amplitude, and symmetry among phases. Microgrid, as a part of the electric power system, has to contribute providing an adequate current waveform in grid connected-mode, as well as to guarantee similar voltage features than the standard requirement given for public distribution grids under normal exploitation conditions in islanded mode. Adequate power quality supply is necessary for the correct compatibility between all the devices connected to the same grid. In this paper, the power quality of microgrids is managed using a Model Predictive Control (MPC) methodology which regulates the power converters of the microgrids in order to achieve the requirements. The control algorithm is developed for the following microgrids working modes: grid-connected, islanded, and interconnected. The simulation results demonstrate that the proposed methodology improves the transient response in comparison with classical methods in all the working modes, minimizing the harmonic content in the current and the voltage even with the presence of non-balanced and non-harmonic-free three-phase voltage and current systems
E-cadherin expression is associated with somatostatin analogue response in acromegaly
Acromegaly is a rare disease resulting from hypersecretion of growth hormone (GH)
and insulin‐like growth factor 1 (IGF1) typically caused by pituitary adenomas, which
is associated with increased mortality and morbidity. Somatostatin analogues (SSAs)
represent the primary medical therapy for acromegaly and are currently used as
first‐line treatment or as second‐line therapy after unsuccessful pituitary surgery.
However, a considerable proportion of patients do not adequately respond to SSAs
treatment, and therefore, there is an urgent need to identify biomarkers predictors
of response to SSAs. The aim of this study was to examine E‐cadherin expression
by immunohistochemistry in fifty‐five GH‐producing pituitary tumours and determine
the potential association with response to SSAs as well as other clinical and
histopathological features. Acromegaly patients with tumours expressing low E‐cadherin
levels exhibit a worse response to SSAs. E‐cadherin levels are associated with
GH‐producing tumour histological subtypes. Our results indicate that the immunohistochemical
detection of E‐cadherin might be useful in categorizing acromegaly
patients based on the response to SSAs.ISCIII‐Subdirección General de Evaluación y Fomento de la Investigación PI13/02043 PI16/00175FEDER PI13/02043 PI16/00175Junta de Andalucía A‐0023‐2015 A‐0003‐2016 CTS‐1406 BIO‐0139Andalusian Ministry of Health C‐0015‐2014CIBERobn PI13/ 02043 PI16/0017
Frequencies of deletereus character in the spanish water dog affecting the breed conservation
321 puppies of the Spanish Water Dog Breed have been used to study the frequency of presentation of several deleterious characters between the years 1995 and 1998. The enogmatism and the monorquidism shown frequencies relatively low, but we stand out these characters because their control is very important for the relationship with respect the adaptive capacity of these animals. In the same way the prognatism and the absence of premolars were present with a frequency slightly high, it must take into account in the selection criteria of the breed. By another side, we found a signifficative association between the presence of heath anomalies and slightly high populational levels of inbreeding, and then we have to avoid these breeding practices in the racial lines presenting this defect.Sobre un total de 321 cachorros nacidos de la raza Perro de Agua Español entre los años 1995 y 1998 se estudian las frecuencias de aparición de diferentes caracteres deletéreos. Los caracteres enogmatismo y monorquidia muestran unas frecuencias relativamente bajas, si bien destacamos la importancia de su control ya que su expresión afecta a la capacidad adaptativa de los animales. Asimismo, el prognatismo y la ausencia de premolares se presentan con unas frecuencias moderadamente altas que recomendamos incluir en los criterios de selección de la raza. Por otra parte, encontramos asociación significativa entre la aparición de anomalías cardíacas y niveles relativamente altos de endogamia en la población por lo que se desaconseja la endocría en las líneas raciales que presentan este defecto
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