6,891 research outputs found
A NEW METHODOLOGY FOR STOCHASTIC SIMULATION OF DAILY CLIMATIC DATA PRESERVING THE INTERANNUAL VARIABILITY
In this work we propose a new methodology to reproduce, by means of simulations, the interannual variability of climatic variables which included only the minimum air temperature. To evaluate the performance of the proposed method, it was maked a comparison with other two weather generators (i.e., PGECLIMA_R and LARS-WG). Moreover, it was utilized the historical series of thirty years of five meteorological stations of the state of Parana - Brazil to generate ten sets of thirty years for each model, which were confronted with the respective historical series. The performance of the proposed model as well as weather generators was evaluated by applying tests of central tendency, variability and distribution. Furthermore, was utilized the statistical measures RMSE, MBE and Willmott agreement index (d). In the stations investigated, the proposed methodology reduced the total error and eliminated the negative bias of interannual variability. In only four (of 600) generated sequences the interannual variability differs significantly from the observed one. The series generated by PGECLIMA_R and LARS-WG presented rejection rate of 99% in the variability test. In this case, the bias was ten times greater and the RMSE was twice times greater than the proposed methodology. The d index was always greater than 0.98 for the five locations in the proposed methodology and around 0.83 in other models. Based on these results, the new methodology provides a relevant contribution concerning the interannual variability of climatic variables
Evaluation of lean practices in warehouses: an analysis of Brazilian reality
© 2020, Emerald Publishing Limited. Purpose: This article aims to investigate the most applied lean warehouse practices in Brazilian warehouses. Design/methodology/approach: To perform this research, three phases were conducted: a literature review, a multiple case study, and an analysis of lean warehouses practices implementation by an engineering committee. Thus, both qualitative and quantitative approaches were used. Additionally, the study has an applied nature, with an exploratory and descriptive character. Findings: Results showed that regardless of the type of criterion used, the most implanted practices are those that do not involve investments in technology. On the other hand, practices like RFID and Cross Docking systems were not found in any of the operations, which shows numerous possibilities for improvement. Originality/value: The main contribution of this article is to initiate a debate about the management and productivity of Brazilian warehouses, a theme still little explored by the academic community despite the importance that the logistic scenario represents for Brazil as an emerging country and leader in Latin America, participating actively in several global supply chains
Effects of mass media on opinion spreading in the Sznajd sociophysics model
In this work we consider the influence of mass media in the dynamics of the
two-dimensional Sznajd model. This influence acts as an external field, and it
is introduced in the model by means of a probability of the agents to
follow the media opinion. We performed Monte Carlo simulations on square
lattices with different sizes, and our numerical results suggest a change on
the critical behavior of the model, with the absence of the usual phase
transition for . Another effect of the probability is to
decrease the average relaxation times , that are log-normally
distributed, as in the standard model. In addition, the values depend on
the lattice size in a power-law form, , where the
power-law exponent depends on the probability .Comment: 11 pages, 8 figures, to appear in Physica
Critical analysis of organizational change process: evidences from a steel company
© 2020, Emerald Publishing Limited. Purpose: The purpose of this paper is to evaluate the main factors that influence the organizational change in a steel company. Design/methodology/approach: The methodological procedures used were literature review and survey. The literature review allowed the listing of 24 factors and these factors were grouped into three constructs (Behavioral Aspects, Cultural Aspects and Management Aspects). The survey allowed the quantification of each factor based on information provided by employees who work in the mentioned company. The data collected were analyzed using the Partial Least Squares-Structural Equation Modeling technique. Findings: For the Behavioral Aspects, the following factors were validated: fear of the unknown; insecurity and anxiety; stress and feeling of suffering. For the Cultural Aspects the following factors were validated: multiculturalism in the company; low degree of risk acceptance and low performance acceptance; excessive concerns about consensus. Finally, for the Management Aspects, the following factors were validated: lack of clarity in communications; lack of alignment of goals; lack of leadership engagement. Originality/value: The results are valuable for the company studied and for other managers interested in subject. The findings presented here can broaden the debate about this topic and contribute with professionals that wish to evaluate the mentioned factors
Variability and spectral energy distributions of low-luminosity active galactic nuclei: a simultaneous X-ray/UV look with Swift
We have observed four low-luminosity active galactic nuclei classified as
Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical
Telescope (UVOT) onboard Swift, in an attempt to clarify the main powering
mechanism of this class of nearby sources. Among our targets, we detect X-ray
variability in NGC 3998 for the first time. The light curves of this object
reveal variations of up to 30% amplitude in half a day, with no significant
spectral variability on this time scale. We also observe a decrease of ~30%
over 9 days, with significant spectral softening. Moreover, the X-ray flux is
~40% lower than observed in previous years. Variability is detected in M 81 as
well, at levels comparable to those reported previously: a flux increase in the
hard X-rays (1-10 keV) of 30% in ~3 hours and variations by up to a factor of 2
within a few years. This X-ray behaviour is similar to that of
higher-luminosity, Seyfert-type, objects. Using previous
high-angular-resolution imaging data from the Hubble Space Telescope (HST), we
evaluate the diffuse UV emission due to the host galaxy and isolate the nuclear
flux in our UVOT observations. All sources are detected in the UV band, at
levels similar to those of the previous observations with HST. The XRT (0.2-10
keV) spectra are well described by single power-laws and the UV-to-X-ray flux
ratios are again consistent with those of Seyferts and radio-loud AGNs of
higher luminosity. The similarity in X-ray variability and broad-band energy
distributions suggests the presence of similar accretion and radiation
processes in low- and high-luminosity AGNs.Comment: 12 pages, 6 figures, in press in MNRA
Election turnout statistics in many countries: similarities, differences, and a diffusive field model for decision-making
We study in details the turnout rate statistics for 77 elections in 11
different countries. We show that the empirical results established in a
previous paper for French elections appear to hold much more generally. We find
in particular that the spatial correlation of turnout rates decay
logarithmically with distance in all cases. This result is quantitatively
reproduced by a decision model that assumes that each voter makes his mind as a
result of three influence terms: one totally idiosyncratic component, one
city-specific term with short-ranged fluctuations in space, and one long-ranged
correlated field which propagates diffusively in space. A detailed analysis
reveals several interesting features: for example, different countries have
different degrees of local heterogeneities and seem to be characterized by a
different propensity for individuals to conform to the cultural norm. We
furthermore find clear signs of herding (i.e. strongly correlated decisions at
the individual level) in some countries, but not in others.Comment: 15 pages, 9 figures, 7 table
Schroedinger cat-like states by conditional measurements on a beam-splitter
A scheme for generating Schr\"{o}dinger cat-like states of a single-mode
optical field by means of conditional measurement is proposed. Feeding into a
beam splitter a squeezed vacuum and counting the photons in one of the output
channels, the conditional states in the other output channel exhibit a number
of properties that are very similar to those of superpositions of two coherent
states with opposite phases. We present analytical and numerical results for
the photon-number and quadrature-component distributions of the conditional
states and their Wigner and Husimi functions. Further, we discuss the effect of
realistic photocounting on the states.Comment: 6 figures(divided in subfigures) using a4.st
Functional Ingredients based on Nutritional Phenolics. A Case Study against Inflammation: Lippia Genus
Epidemiological studies have reported convincing evidence that natural dietary compounds
may modify inflammation, it being an important event described in the pathophysiology of age-related
infirmity. Among different dietary components, nutritional phenolics have demonstrated links to a
lower risk of inflammation in the most common degenerative and chronic diseases. In this way, the
healthy potential of phenolics against inflammation and the emergence of new functional ingredients
have caused an enhancement of nutraceutical and functional food formulation. The present review
focuses on: (a) nutritional phenolics and their effects on inflammation and (b) functional ingredients
based on phenolic compounds with anti-inflammatory properties. Furthermore, the emerging interest
in health-promoting products by consumers has caused an increase in the demand for functional
products and nutraceuticals. Additionally, this review includes a case study of the Lippia genus,
which has shown anti-inflammatory effects claiming to be a natural alternative for the management
of this physiological disorder. This report is a practical tool for healthcare providers.This work was funded by projects AGL2015-67995-C3-2-R and IJCI2015-26789 (Spanish Ministry of
Science and Innovation), P11-CTS-7625 (Andalusian Regional Government Council of Innovation and Science) and
RTI2018-096724-B-C22 (Ministry of Science, Innovation and Universities). The author Leyva-Jimenez gratefully
acknowledges the Spanish Ministry of Economy and Competitiveness (MINECO) for the FPI grant BES-2016-076618
given to develop this work
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