955 research outputs found

    A recoverable production planning model

    Get PDF
    Aware of the importance of developing new alternatives to improve the performance of the companies, our purpose in this paper is to develop a medium term production planning model that deals with the concepts of Partnership and Reverse Logistics. Our model takes advantage of the synergies of integration, developing a model for global production planning that generates the optimal production and purchasing schedule for all the companies integrating a logistic chain. In a second part of the paper we incorporate products returns to the first model proposed, and analyze the implications they have over this model. We use some examples with different configurations of supply chains varying the number of production plants, distribution centers and recovery plants. To solve the model we have combined optimization and simulation procedures.Reverse logistics, production planning, remanufacturing, returns, supply chain management, simulation, optimization

    Prehistoric psychotropic consumption in Andean Chilean mummies

    Get PDF
    Hallucinogenic plants are often regarded as the main source of psychoactive drugs in antiquity to reach deep altered states of consciousness^1,2^. Many researchers believe this was particularly true during the Tiwanaku empire expansion, circa (500-1000 A.D.), along the Atacama Desert of Chile. Highly decorated snuffing tablets and tubes are often found as grave goods during this period^3,4,5,6,7,8^. Until now the type of drugs consumed in this paraphernalia has been unclear. From the modern city of Arica, naturally mummified human bodies with abundant hair provided a unique opportunity to test for hallucinogenic plants consumed in Andean prehistory. Analysis by gas chromatography and mass spectrometry demonstrated the presence of harmine. The Banisteriopsis vine, commonly called Ayahuasca, was the probable source. This is the first confirmed evidence of psychoactive plant consumption in pre-Hispanic Andean populations along the Atacama coastal region. Of the 32 mummy hair samples analyzed 3 males tested positive for harmine. This alkaloid aids in the catalysis and synergic effects of powerful hallucinogenic drugs. The consumption of harmine was likely related to medicinal practices and not exclusively ingested by shamans. Another important aspect of this evidence is that Banisteriopsis is an Amazon plant. It does not grow in the Atacama coastal region. Thus, our findings reveal extensive plant trade networks in antiquity between the coast, desert, highlands, and Amazon basin. The excellent preservation of human organic specimens, the use of gas chromatography and mass spectrometry allowed us to map and demonstrate the consumption of psychoactive compound plants in Andean prehistory. In addition, our findings open the door for future studies to debate the consumption and social role of ancient psychoactive and hallucinogenic plants

    Mycoplasma isolation in milk samples from dairy herds in Chile

    Get PDF
    Mycoplasma bovine mastitis is a highly contagious disease, usually associated with clinical cases refractory to antibiotic treatment. The aim of this study was the isolation of Mycoplasma species in cattle milk samples from dairy herds in Chile. Bulk tank milk samples selected by convenience from 91 Holstein Friesian dairy herds located in Los Rios (66) and Los Lagos (25), the two most important dairy Regions in the country, were collected. Additionally, 100 individual milk samples from cows with a high incidence of clinical mastitis, refractory to antibiotic therapy, and negative bacteriological results for traditional mastitis pathogens, all from the BiobĂ­o Region and received in our diagnostic laboratory, were included. All samples were cultured for 10 days on PPLO medium. The differentiation of suspect colonies between genus Mycoplasma and Acholeplasma was performed by the digitonin test and a specific PCR. The species identification was performed by a M. bovis specific PCR and 16S rRNA sequencing. Mycoplasma was isolated from 3 (3.3%) bulk tank milk samples and 2 (2%) individual cow milk samples. All colonies were identified as Mycoplasma by the digitonin test and by a specific PCR. At species level, one strain isolated from a bulk tank milk sample was identified as M. bovis. The remaining two strains isolated from bulk tank milk samples were identified as M. bovigenitalium, while the two strains isolated from milk of individual cows were identified as M. alkalescens. These results show that not only M. bovis is present in Chilean dairy herds, but also other pathogenic species not previously described in Chile such as M. bovigenitalium and M. alkalescens, which pose a potential risk for dairy herds in southern Chile

    Geographic Patterns of Inversion Polymorphism in the Second Chromosome of the Cactophilic Drosophila buzzatii from Northeastern Argentina

    Get PDF
    The inversion polymorphisms of the cactophilic Drosophila buzzatti Patterson and Wheeler (Diptera: Drosophilidae) were studied in new areas of its distribution in Argentina. A total of thirty-eight natural populations, including 29 from previous studies, were analyzed using multiple regression analyses. The results showed that about 23% of total variation was accounted for by a multiple regression model in which only altitude contributed significantly to population variation, despite the fact that latitude and longitude were also included in the model. Also, inversion frequencies exhibited significant associations with mean annual temperature, precipitation, and atmospheric pressure. In addition, expected heterozygosity exhibited a negative association with temperature and precipitation and a positive association with atmospheric pressure. The close similarity of the patterns detected in this larger dataset to previous reports is an indication of the stability of the clines. Also, the concurrence of the clines detected in Argentina with those reported for colonizing populations of Australia suggests the involvement of natural selection as the main mechanism shaping inversion frequencies in D. buzzatii

    A time-series forecasting performance comparison for neural networks with state space and ARIMA models

    Get PDF
    This research focuses on the development of an automated forecasting procedure that implement State Space (SS), Auto Regressive Integrated Moving Average (ARIMA), and Neural Networks (NN) to identify the best forecasting strategy for time series with numerous patterns. The proposed approach is applied on multiple time series exhibiting different series patterns from the M4 competition. Based on our study, the performance of ARIMA models showed superior results when compared to the ETS performance for seasonal data. In addition, NN and ARIMA showed a higher performance for cyclical and non-stationary data. NN performance was competitive in all types of data patterns. ARIMA stepwise selection procedure proved to be the most accurate in general for all the series. This delimited development is part of a comprehensive application that will encompass a dashboard tool designed to automatize forecasting procedures of different types of time series presented in the industry Keyword

    Assessing organizational behavior: a case study in a colombian retail store

    Get PDF
    In this research, significant components of organizational behavior in an actual commercial retail store located in Colombia, were further considered and investigated. The business case was analyzed by applying a structured questionnaire in the company. It was concluded that the success of the company is influenced by factors such as motivation, job satisfaction, emotions and decision making, indicating that perception factors and attitudes need reinforcement. In addition, recommendations for the intervention of organizational behavior, as well as the perspective of reducing the negative impacts that these findings might have on the obtained results are also proposed

    An organizational behavior study to evaluate project performance

    Get PDF
    In this research, significant components of organizational behavior in a commercial company were investigated and studied. In order to perform this task, we analyzed a business case where a structured questionnaire was applied into the company. We assessed that the success of the company is influenced by factors such as motivation, job satisfaction, emotions and decision making, with the indication that perception factors and attitudes are in need of reinforcement. In addition, recommendations for intervention of organizational behavior are also presented, with the perspective of reducing the negative impact that these findings might have on the results obtained

    Evolution of male genitalia: environmental and genetic factors affect genital morphology in two Drosophila sibling species and their hybrids

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The rapid evolution of genital morphology is a fascinating feature that accompanies many speciation events. However, the underlying patterns and explanatory processes remain to be settled. In this work we investigate the patterns of intraspecific variation and interspecific divergence in male genitalic morphology (size and shape) in the cactophilic sibling species <it>Drosophila buzzatii </it>and <it>D. koepferae</it>. Genital morphology in interspecific hybrids was examined and compared to the corresponding parental lines.</p> <p>Results</p> <p>Despite of being siblings, <it>D. buzzatii </it>and <it>D. koepferae </it>showed contrasting patterns of genital morphological variation. Though genitalic size and shape variation have a significant genetic component in both species, shape varied across host cacti only in <it>D. buzzatii</it>. Such plastic expression of genital shape is the first evidence of the effect of rearing substrate on genitalic morphology in <it>Drosophila</it>. Hybrid genital morphology was not intermediate between parental species and the morphological resemblance to parental strains was cross-dependent.</p> <p>Conclusion</p> <p>Our results suggest the evolution of different developmental networks after interspecific divergence and the existence of a complex genetic architecture, involving genetic factors with major effects affecting genital morphology.</p

    Analysis of competitiveness in supply chain integration and logistics: an evidence from a public hospital network

    Get PDF
    Healthcare systems are recognized for their disarticulated logistics models due to their interconnected services complex structure. There is evidence in the literature that these systems require the implementation of supply chain management practices to strengthen their integration with customers and suppliers and improve their competitiveness. Then, this research aimed to analyze competitiveness in a supply chain integration and logistics for a Colombian public hospital applying a competence and capability assessment. The results show that the supply chain integration competitiveness of the studied hospital is 72.24%, and the logistics competitiveness is 77.79%. Based on the Bowersox model, most performance results are above the defined threshold set by the performance of established world-class companies, showing an acceptable level. To reduce the identified GAPs, we provided strategies for the improvement of competitiveness in supply chain integration and logistics for the selected Colombian public hospital

    A systematic business process management application of an imports process on a commercial company

    Get PDF
    In recent years, companies have tried to understand their processes' functionality and response capability to the forces of the environment using information systems. This research developed an automated Business Process Management (BPM) model of the import process in a commercial company located in Colombia. First, a survey was applied to the stakeholders to ascertain the challenges presented at the company' import process. Later, a process flow was proposed based on BPM. The model results indicate a 43% reduction in the execution times of activities in the import area, a 30% decrease in default costs, and a 70% reduction in storage costs for the company
    • …
    corecore