3,199 research outputs found

    The Impact of Education, Gender, Age and Leadership Experience On Preferences In Leadership

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    Meta-analytic studies have found that men and women are different in areas such as how they approach morality, forgiveness and leadership, Similarly, meta-analyses have found that increased education is related to increased self-esteem, job attitudes and social capital, In this study, 577 working adults from the state of Texas completed the Project Globe Leadership Questionnaire. The participants indicated to what degree 24 leadership behaviors contributed to or inhibited outstanding leadership. This study found that both gender and education were related to the intensity with which participants believed particular leadership characteristics contributed to and inhibited outstanding leadership. Women held stronger opinions than men about the benefits of five aspects of leadership generally considered to contribute to outstanding leadership: integrity, team-oriented, participative, humane-oriented and diplomatic, Women also held stronger opinions about the liabilities of four aspects generally considered to inhibit outstanding leadership: conflict inducer, self-protective, autocratic and malevolent. Formal education was related to stronger ratings of the importance of integrity, charisma, performance and team orientation. Formal education was also related to stronger ratings of the degree to which self-protective, face-saving, autocratic, self-centered and malevolent behaviors inhibit outstanding leadership

    Blood lead levels in pregnant women of high and low socioeconomic status in Mexico City.

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    This study examined the determinants of blood lead (BPb) in 513 pregnant women in Mexico City: 311 from public hospital prenatal clinics, representing primarily women of low socioeconomic status (SES), and 202 from private hospitals, primarily women of high SES. Overall, BPb levels ranged from 1.38 to 29 micrograms/dl, with geometric means of 6.7 and 11.12 micrograms/dl for women from private and public hospitals, respectively. The crude geometric means difference obtained by t-test was 4.42 (p < 0.001). BPb was measured from January 1994 to August 1995 and showed higher levels during fall and winter and lower levels during spring and summer. The main BPb determinants were the use of lead-glazed ceramics in women from public hospitals and season of the year in women from private hospitals. Consumption of tortillas (corn bread rich in calcium) decreased BPb levels in the lower SES group, but the relationship was not statistically significant (p > 0.05). Consumption of milk products significantly (p < 0.05) reduced BPb levels in the higher SES group. In 112 women whose diets were deficient in calcium, taking calcium supplements lowered their blood lead levels about 7 micrograms/dl. A predictive model fitted to these data, using the strongest predictors plus gestational age, showed a difference of 14 micrograms/dl between the best and worst scenarios in women from public hospitals. Avoiding use of lead-glazed ceramics, consuming diets rich in calcium, and, if needed, taking calcium supplements, would be expected to result in substantial lowering of BPb, especially in pregnant women of low socioeconomic status

    S-Transform based Fault Detection Algorithm for Enhancing Distance Protection Performance

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    This paper presents a new fault detection algorithm based on the Fast Discrete Stockwell Transform. The algorithm can improve the functionality of existing distance protection and resolve shortcomings identified during the fault detection process in case of fault occurrence in systems with a high penetration of power electronics-based generators. Reported results of the operation of commercial distance relays of four different vendors show that all relays experience difficulties during ungrounded faults. An RTDS testbed is developed for extensive hardware in the loop testing, comprising electromagnetic transient models of Type-3 and Type-4 wind generators. The proposed algorithm successfully overcomes the identified problems for cases where commercial relays maloperate. The threshold parameters for the fault detection are set by using the energy content attributed to the Fast Discrete Stockwell Transform time–frequency domain signal. Other distance protection modules such as the determination of directionality, phase selection and the computation of the impedance, which are necessary for the protection selectivity, are developed based on currently available solutions applied in commercial relays. The new algorithm has been extensively tested using RTDS for various fault conditions and the obtained results are reported in the paper

    Seasonal and Spatial Patterns in Salinity, Nutrients, and Chlorophyll α in the Alvarado Lagoonal System, Veracruz, Mexico

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    Ten monthly collections, distributed among three seasons, were taken from July 2000 to June 2001 in the Alvarado lagoonal system, Veracruz, Mexico. Variables measured in situ included dissolved oxygen, salinity, and water temperature. Water samples were collected to determine concentrations of ammonium, nitrates, nitrites, orthophosphates, total phosphorus and chlorophyll α. Collections representing the rainy season were taken in September and October, those for the nortes season were taken in November, December, and January, and dry season collections were taken during February, March, May June, and July. There was seasonal and spatial variation in nutrient concentrations, and they were related to the discharge of the rivers; concentrations increased during the rainy and nortes seasons. Other factors affecting water quality included the constant discharge of organic materials into the system, resuspension of sediments during the nortes season and the biological activity within the system that assimilated the nutrients in the water. The Alvarado lagoonal system has three separate zones based on physicochemical characteristics; Camaronera Lagoon, Buen Pais Lagoon and the urban zone of Alvarado Lagoon, and the river zone in Alvarado Lagoon

    Lindane and Endosulfan Sulfate Isomers in Crassostrea virginica (Gmelin, 1791) Oyster Populations in Lagoon Systems from Central Gulf of Mexico

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    The aim of this study was to determine Lindane and Endosulfan Sulfate isomers in Crassostrea virginica oyster populations (Gmelin, 1791) in the Mandinga and Alvarado lagoon systems located in the central Gulf of Mexico. Samples were taken from the main oyster banks of each lagoon system, during the three representative seasons of the region, wet, dry and north winds. By means of free diving, 30 commercial size oysters (7 ± 3 cm) were collected in four oyster banks or stations of the Mandinga lagoon system, totaling 360 organisms, while in the Alvarado lagoon system there were a total of 90 oysters during the annual cycle. Concentration of lindane and endosulfan sulfate isotopes in C. virginica was performed with a gas chromatograph (Thermo Electron Model Trace GC Ultra 115V, Thermo Fisher Scientific Inc©, Monterrey, Nuevo León, México) with an Electron capture detector. Results showed that in the Alvarado Lagoon system mean concentrations of C. virginica oysters for lindane pesticide were 4.11 ± 3.83 ng⋅g-1, whereas for the Mandinga lagoon system, were 8.69 ± 5.15 ng⋅g-1. Endosulfan sulfate showed the highest average concentration in the Mandinga lagoon system with 24.68 ± 1.20 ng ⋅g-1. In addition, the endosulfan sulfate presents differences in its spatial distribution; high concentration levels in the Mandinga lagoon system whereas the lindane heterogeneity at all sampling points in both lagoons. Values of concentrations and relationships between compounds suggest recent contributions that could correspond to the excessive fluctuations of water discharged into the lagoon caused by the atypical rains of the year of sampling. It was concluded that endosulfan sulfate and lindane show concentration in all the points of sampling in both lagoons

    CARWASH WASTEWATERS: CHARACTERISTICS, VOLUMES, AND TREATABILITY BY GRAVITY OIL SEPARATION

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    The aim of this research was to determine the characteristics, volumes and treatability of Full-service carwash wastewaters in Toluca (Mexico State). The average water use for Exterior-only wash was 50 L per small-size car and 170 L per medium-size vehicle (pick up, van or light truck). The Full-service wash (exterior, engine and chassis) required 170 L per small-size car and 300 L per light truck. Wastewaters were generally emulsified and contained high contaminant loads (in average, 1100 mg/L oil and grease, 4500 mg/L COD and 3500 mg/L Total Suspended Solids). Gravity oil separators used in the car washing facilities were able to reduce the pollutant loads (showing a 80 % efficiency) but usually not enough to meet the sewer discharge standards or reuse requirements. The data provided by the study are useful for screening the applicable technologies and setting the design capacity of the reclaim systems that are needed in the Mexican car washing sector

    Properties of iron-modified-by-silver supported on mordenite as catalysts for nox reduction

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    A series of mono and bimetallic catalysts based on a Fe-Ag mixture deposited on mordenite was prepared by ion-exchange and evaluated in the catalytic activity test of the de-NOx reaction in the presence of CO/C3H6. The activity results showed that the most active samples were the Fe-containing ones, and at high temperatures, a co-promoter effect of Ag on the activity of Fe catalysts was also observed. The influence of the order of cation deposition on catalysts formation and their physicochemical properties was studied by FTIR (Fourier Transform Infrared Spectroscopy) of adsorbed NO, XANES (X-ray Absorption Near-Edge Structure), and EXAFS (Extended X-ray Absorption Fine Structure) and discussed in terms of the state of iron. Results of Fe K-edge XANES oscillations showed that, in FeMOR catalysts, iron was present in a disordered state as Fe3+ and Fe2+. In FeAgMOR, the prevailing species was Fe3+, while in the AgFeMOR catalyst, the state of iron was intermediate or mixed between FeMOR and FeAgMOR. The Fe K-edge EXAFS results were characteristic of a disordered phase, the first coordination sphere being asymmetric with two different Fe-O distances. In FeAgMOR and AgFeMOR, coordination of Fe-O was similar to Fe2O3 with a few amount of Fe2+ species. We may conclude that, in the bimetallic FeAgMOR and AgFeMOR samples, a certain amount of tetrahedral Al3+ ions in the mordenite framework is replaced by Fe3+ ions, confirming the previous reports that these species are active sites for the de-NOx reaction. Based on the thermodynamic analysis and experimental data, also, it was confirmed that the order of deposition of the components influenced the mechanism of active sites&rsquo; formation during the two steps ion-exchange synthesis

    Project: Center for Diabetes and Metabolism [Centro de Diabetes y Metabolismo: CeDiMet], a collaborative dream comes true

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    Reynosa urban area has 690,000 inhabitants (384,000 adults \u3e20 years old), 35% moved from other states. The use of cell phones is in 81%, personal computer or laptop with 29%. The prevalence of overweight is 39%, obesity 36%, and T2D 13%. The expected adult population with T2D is 49,900 individuals. The are 5 clinics prepared to attend T2D, and few with specialized personnel. The CeDiMet is a collaborative clinic involving health personnel and researchers from the Universidad Mexico Americana del Norte, Universidad Autonoma de Tamaulipas, Hospital General de Mexico “Dr. Eduardo Liceaga”, University of Texas Rio Grande Valley, and the Texas Diabetes Institute in San Antonio. The funding source comes from private companies in Reynosa. The clinical structure includes physicians, nurses, nutritionists, psychologists, and a section for telemedicine for consulting specialists from USA and Mexico City. Besides clinical attendance, the CeDiMet will conduct educational activities in offices, factories, churches, and schools for prevention of obesity complications (T2D and hypertension), early detection of diabetic foot, fatty liver, and endothelial damage. “Tree of Health in the Family” is a program to encourage youth to know and understand the metabolic problems in their families to focus on prevention. Recently, we obtained a grant from COTACyT to explore the effect of COVID-19 in a cohort of 200 students and their families. The analysis of post-traumatic stress due to confinement and antibodies concentration to detect contacts and its association with metabolic problems is an example of the research we can perform
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