Antibiotic resistance and tolerance to simulated gastrointestinal conditions of eight hemolytic Bacillus pumilus isolated from pulque, a traditional Mexican beverage

Raquel González-Vázquez,Lino Mayorga-Reyes,Armando Monroy-López,Luis A. Reyes-Nava,Yadira Rivera-Espinoza,Alejandro Azaola-Espinosa 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.2

Traditional fermented sap beverages from two provinces of Mexico were studied for the isolation of pathogenic bacteria from these beverages. Eight strains of hemolytic Gram positive bacteria, identified as Bacillus pumilus (B. pumilus), were isolated. They showed different antibiotic resistance profiles and tolerances to the simulated gastrointestinal conditions. All the B. pumilus isolated were resistant to at least one antibiotic tested. Regarding the simulated gastrointestinal conditions, strains S1 and S3 were able to tolerate all the conditions. Hemolytic activity has been associated with a health risk and is often considered as a virulence determinant associated with pathogenicity. Therefore, the hemolytic activity along with the ability to tolerate gastrointestinal conditions and the resistance to antibiotics exhibited by B. pumilus strains S1 and S3 could be associated with a health risk for pulque consumers.

SUCCESS FACTORS IN THE FRONT END OF INNOVATION

Alexander Vélez,Jose M Barrutia,Carmen Etxebarria 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

The aim of this research is to improve our understanding of the success factors of the front end of innovation (hereinafter, front end) for highly innovative products. Our approach is uncommon in three ways. First, the front end is not considered as a uniform whole, but as consisting of three heterogeneous phases/outcomes, which could require a different mix of resources. Second, a comprehensive range of explanatory factors is scrutinized, including company-, people- and openness-related factors. Third, openness is represented not only by relational breadth and depth, but also relational quality. We examine information originating from two different sources: (1) an ad-hoc survey which provided information from a representative sample of 190 companies, and (2) a secondary data source compiled by the Statistical Office of a regional government in Spain. By using two information sources, we were able to triangulate data and control for validity and common method bias. We found that success in each of the three phases of the front end of new product development is explained by different factors. Relational quality, strategic flexibility and creative culture contribute to the creativity of ideas. The drivers of product definition proficiency appear to be relational quality, technical expertise and creative culture. Finally, front end and technical expertise, leadership and relational depth contribute to project plan proficiency. Overall, our research suggests that empirical studies that consider the front end as a whole and do not consider openness, and, in particular, relational quality, could be misleading.

Open Loop Robust Equilibria in Uncertain Discrete Time Games

Fernando Guerrero Vélez,Manuel Jiménez Lizárraga,Celeste Rodriguez Carreon 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2

This paper tackles the problem of a discrete time N players game affected by some sort of time-varying uncertain perturbation. The philosophy of the uncertainty worst case scenario with respect to the i-player is developed to derive necessary and sufficient conditions for the existence of an Open Loop Robust Nash Equilibria. Such conditions are presented in terms of the solvability of a set of discrete time Riccati type equations with some boundary conditions. As an illustration of the solution, a simulation of the coordination of a two-echelon supply chain with uncertain seasonal fluctuations in the demand is developed.

Acute toxicity of aqueous extract of Ambrosia arborescens Mill. on biochemical and histopathological parameters in rats

Silva-Correa Carmen R.,Villarreal-La Torre Víctor E.,González-Siccha Anabel D.,Cruzado-Razco José L.,González-Blas María V.,Sagástegui-Guarniz William Antonio,Calderón-Peña Abhel A.,Aspajo-Villalaz Ci 한국독성학회 2022 Toxicological Research Vol.38 No.2

Medicinal plants play an important role in the management of various diseases, so their use has become widespread. However, in some cases the population uses plant species regardless of the toxicity they may possess. The objective of this study was to evaluate the acute toxicity of aqueous extract from the leaves of Ambrosia arborescens Mill. on the biochemical and histopathological parameters of albino Holtzman rats. To do this, the leaves of A. arborescens were collected in the province of Julcan, La Libertad Region—Peru. OECD (Organisation for Economic Cooperation and Development) guideline 423 was conducted, forming experimental groups of 10 animals each one (5 males and 5 females): Group I (Control), which received 2 mL physiological saline solution (SSF 0.9%), Groups II and III (A. arborescens-300 and A. arborescens-2000), which were given the aqueous extract leaves of A. arborescens in a single dose of 300 and 2000 mg/kg/day, respectively. On the 14th day of exposure, biochemical (creatinine, ALT and AST) and histopathological parameters were measured. The results show that the aqueous extract of A. arborescens at the dose of 2000 mg/kg produces an increase in biochemical parameters which is related to histopathological analysis of liver and renal tissue with mild congestion. The study concludes that the aqueous extract leaves of A. arborescens has a LD50 greater than 2000 mg/kg and produces mild congestion in kidneys and liver, but showed no significant toxicological changes in the other albino Holtzman rats organs.

Teacher stress factors and performance in high schools in Ecuador

Esteban Vázquez-Cano,Ana Isabel Holgueras-González 한국교육개발원 2019 KEDI Journal of Educational Policy Vol.16 No.2

The government of Ecuador has invested heavily in education in recent years, and this has affected the socio-educational context and professional role of teachers in that country. This study aims to determine the main factors that can cause stress among teaching professionals in Ecuador, by means of a quantitative methodology, and factor and regression analyses. The results show that the main stress factors affecting teachers relate to poor working conditions (20.3%), a negative professional environment (13.7%), excessive workload (12.5%), assaults and lack of appreciation (9.4%), and performance assessment (3.9%). Thus, the determination of the main stress factors in a specific socio-educational context contributes to the international understanding of the socio-professional profile of the teacher and could favour the measures to minimize teachers’ stress.

The value of sub-national data: The dynamics of contentious politics in Nepal

Johannes Vüllers,Belén González 한국외국어대학교 국제지역연구센터 2020 International Area Studies Review Vol.23 No.3

Over the last decade, a renewed interest in the empirical analysis of contentious politics has led to significant improvements in the quality and quantity of data. The related wave of research has thus turned to analysis of the dynamics of contentious politics from a comparative perspective. Unfortunately, these studies use country level datasets for their analysis, creating a mismatch between the original actor-based theoretical framework and the empirical conceptualization of contentious collective action. We discuss the conceptual challenges this theoretical-empirical gap generates and highlight how contentious dynamics can be studied with a bottom-up subnational approach. To do so, we present a new fine-grained dataset of contentious collective action in post-conflict Nepal (2007 to 2010). We descriptively show how this type of data can help us improve our understanding of repertoires of contentious politics. This paper highlights the relevance of gathering information on active organizations to study the inherent dynamics of contentious politics.

Relationship among blood indicators of lipomobilization and hepatic function during early lactation in high-yielding dairy cows

Felix Diaz González,Rodrigo Muiño,Víctor Pereira,Rómulo Campos,José Luis Benedito 대한수의학회 2011 Journal of Veterinary Science Vol.12 No.3

Blood indicators are used as a tool to diagnose metabolic disorders. The present work was conducted to study the relationships among blood indicators of lipomobilization and hepatic function in high-yielding dairy cows. Two groups of Holstein cows were studied: 27 early lactation cows and 14 mid lactation cows from four different herds with similar husbandry characteristics in Galicia, Spain. Blood samples were obtained to measure beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), triglycerides (TG), and the activity of aspartate transaminase (AST) and gamma-glutamyl transferase. Cows in early lactation had higher levels of BHB and NEFA than mid lactation cows. High lipomobilization (NEFA > 400 μmol/L) was detected in 67% and 7% of early lactation and mid lactation cows, respectively, while subclinical ketosis (BHB > 1.2 mmol/L) was detected in 41% and 28% of the early lactation and lactation cows, respectively. TG concentrations were low in all cows suffering subclinical ketosis and in 61% of the cows with high lipomobilization. During early lactation, 30% of cows suffered hepatic lipidosis as detected by levels of AST. Compromised hepatic function was observed in early lactation cows as shown by lower concentrations of glucose, total protein, and urea.

Frequency spectra characterization of noncoding human genomic sequences

O. Paredes,Rebeca Romo‑Vázquez,Israel Román‑Godínez,Hugo Vélez‑Pérez,Ricardo A. Salido‑Ruiz,J. Alejandro Morales 한국유전학회 2020 Genes & Genomics Vol.42 No.10

Background Noncoding sequences have been demonstrated to possess regulatory functions. Its classifcation is challenging because they do not show well-defned nucleotide patterns that can correlate with their biological functions. Genomic signal processing techniques like Fourier transform have been employed to characterize coding and noncoding sequences. This transformation in a systematic whole-genome noncoding library, such as the ENCODE database, can provide evidence of a periodic behaviour in the noncoding sequences that correlates with their regulatory functions. Objective The objective of this study was to classify diferent noncoding regulatory regions through their frequency spectra. Methods We computed machine learning algorithms to classify the noncoding regulatory sequences frequency spectra. Results The sequences from diferent regulatory regions, cell lines, and chromosomes possessed distinct frequency spectra, and that machine learning classifers (such as those of the support vector machine type) could successfully discriminate among regulatory regions, thus correlating the frequency spectra with their biological functions Conclusion Our work supports the idea that there are patterns in the noncoding sequences of the genome.

Zn-22Al-2Cu Alloy Phase Transformations at Different Homogenizing Temperatures

Héctor Javier Dorantes-Rosales,Víctor Manuel López-Hirata,Ramón Esquivel-González,Jorge Luis González-Velazquez,Joel Moreno-Palmerin,Antonio Torres-Castillo 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.3

The effect of the homogenizing temperature on phase transformations and hardening behavior was studied in a Zn-22Al-2Cu (wt%) alloy homogenized for 7 days at 315, 350, and 390°C. The homogenized alloy was subsequently quenched and aged naturally at room temperature or artificially at 200°C for different time periods. The β phase was unstable at room temperature and it decomposed through the β→α+ηreaction during natural aging. An increase in the homogenizing temperature caused a decrease in the kinet-ics of the decomposition of the β phase in the alloy. Natural aging also caused an increase in the hardness due to the formation of nanometric grains with α and η phases and the presence of an intermetallic εphase. This result agrees with the time exponents (n) between 1.5 and 2.6, which were obtained using the Johnson-Mehl-Avrami-Kolmogorov equation for the decomposition of the β phase. The transformed frac-tion curves exhibited the fastest and slowest growth kinetics of the â phase decomposition at homogeniz-ing temperatures of 350 and 390°C, respectively. The artificial aging induced the formation of equilibrium phases and began a decrease in hardness due to the coarsening process of the equilibrium α, η, and τ'phases.

APPROXIMATIONS TO THE MAGIC FORMULA

A. LÓPEZ,P. VÉLEZ,C. MORIANO 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.2

Pacejka’s tire model is widely used and well-known by the automotive engineering community. The magic formula describes the brake force, side force and self-aligning torque in terms of the longitudinal slip and slip angle, plus several corrections. This paper uses approximation theory to obtain different types of approximations to the magic formula: rational functions (RA) resulting from the Remez algorithm, expansions in a series of Chebyshev polynomials (ACh), a series of Chebyshev rational polynomials (ARChPs), a series of rational orthogonal functions (ORF) and a series of ARChPs that result from grade-1 ORFs. The last expansion shows the fastest convergence and most effective computation. Jacobi rational polynomials can also be obtained to complement this expansion and facilitate fine-tuning in specific areas of the error curve. This work is complemented by obtaining the original rational approximations to the inverse tangent function, which take advantage of the curve symmetry to reduce the computation load and provide models that include the influence of the vertical load. The convergence properties of the development in series and the error values resulting from numeric examples for the three types of stress are shown. The proposed final ARChP expressions show very low error (1%) compared to the original magic formula. They can be computed 20 times faster; they can be evaluated, derived and integrated analytically easily; and their coefficients can be obtained from tests using common least-squares algorithms.