Comparación de la comunidad microbiana en fotobiorreactores tratando purines de cerdo

En este trabajo se utilizó la técnica DGGE (electroforesis en gel desnaturalizante en gradiente) para comparar la comunidad microbiana en 4 fotobiorreactores tratando purines de cerdo, en diferentes concentraciones (1:10, 1:20) y condiciones de luz y temperatura (indoor, outdoor). Tras la extracción del ADN genómico y amplificación por PCR de las regiones V6-V8 del ARNr bacteriano, se analizaron los amplicones mediante DGGE, obteniendo el perfil electroforético de cada muestra. Según el índice de Diversidad de Shannon-Wiener, la diversidad bacteriana fue media (2.6 en 3 reactores) o baja (2.1 en el reactor 1:20 outdoor). El índice de similaridad mostró poca variabilidad entre las muestras, siendo las más semejantes entre sí las de los reactores indoor (83.4%). Las bacterias identificadas a partir de las bandas más significativas de cada perfil electroforético, utilizando las bases de datos RDP y BLAST, pertenecen mayoritariamente al filo Proteobacteria, siendo especialmente representativo el género Psychrobacter.Departamento de Ingeniería Química y Tecnología del Medio AmbienteGrado en Ingeniería Químic

New gaussian points for the solution of first order ordinary differential equations

The Gauss Radau and the Lobatto points make use of the roots of the Legendre polynomial located within the step [-1,1]. In this paper, a new set of Gaussian points has been proposed and used as collocation points for the construction of block numerical methods for the solution of first order IVP through transformation within the step [Xn,Xn+2]. The new points resulted into stable numerical block methods of order 2m suitable for solving both stiff and non-stiff IVP. Numerical experiments carried out using the new Gaussian points revealed there efficiency on stiff differential equations. The results also reveal that methods using the new Gaussian points are more accurate than those using the standard Gaussian points on non-stiff initial value problems. Keywords: Gaussian points, Collocation points, Legendre polynomial, Gauss,Lobatto, Block integrators, stiff and non-stiff IVP’

Numerical Solution of Ordinary Differential Equations (ODES) from Reformulated block 3-step AdamsBashforth method

In this paper, efficient AdamsBashforth Runge-Kutta (ABRK) method are constructed.This is achieved by reformulating the block AdamsBashforth methods as a class of Runge-Kutta methods for 3-step.The reformulated methods are of orders 4 and their absolute stability regions construc ted are shown to be A-Stable.The newly constructed methods are tested on non stiff initial value problems and the solution reveals that the the methods are efficient

Prevalence of Chronic Health Conditions among Latinos in the United States between 1990 and 2011

Introduction: This study examines the prevalence of five major chronic health conditions – heart disease, stroke, cancer, arthritis, and diabetes – among adults 18 years of age and older in the United States between 1999 and 2011. Methods: The data used in this report come from the Center for Disease Control and Prevention’s (CDC) National Center for Health Statistics, Health Data Interactive tables. Patterns were examined by age structure among the four largest race/ethnic groups in the U.S., and among the two largest Latino subgroups in the U.S. (Mexicans and Puerto Ricans) Results: Latinos had higher rates of diabetes than did non-Hispanic whites and Asians, with no change in the disparity between those rates from 1999 to 2011. Latinos had lower rates of heart disease than did non-Hispanic whites and non-Hispanic blacks. The Latino population had lower rates of arthritis than did non-Hispanic whites and non-Hispanic blacks. The comparatively high rates of diabetes but low rates of heart disease and arthritis among Latinos may be due to the younger age structure of the Latino population in the United States. Mexicans had lower rates of all five chronic conditions examined in this report – heart disease, stroke, cancer, arthritis, and diabetes – than did Puerto Ricans. Discussion: The lower rates of chronic conditions among Mexicans compared to Puerto Ricans may be explained by a lack of health care access among Mexicans. Mexicans may have lower rates than Puerto Ricans simply because their chronic conditions go undiagnosed and so are underreported. Other possible reasons for the differences in rates between Mexicans and Puerto Ricans – nativity, exercise, poverty rates, and age structure – did not explain the differences

Fouling and Cleaning in Osmotically Driven Membranes

Fouling is a phenomenon that occurs in all membrane processes. It is a complex problem, which limits the full operation of this technology. Fouling in pressure-driven membranes (PDMs) has been studied extensively, and the occurrence is well understood in that methods of mitigation have been proposed; however, limitations still occur for their full implementation. The use of osmotically driven membranes (ODMs) for water treatment is an emerging technology, which has shown some advantages such as low hydraulic pressure operation, high solute rejection and high recovery over PDMs. However, like in PDMs, fouling still presents a challenge. This chapter is aimed at evaluating the impact of fouling on the ODM performance, exploring the factors and mechanisms governing the fouling behaviour, developing approaches for mitigating fouling, elucidating the effect of membrane fouling and providing mitigation strategies as well as the causes of fouling in ODMs

On some properties of the block linear multi-step methods

The convergence, stability and order of Block linear Multistep methods have been determined in the past based on individual members of the block. In this paper, methods are proposed to examine the properties of the entire block. Some Block Linear Multistep methods have been considered, their convergence, stability and order have been determined using these approaches. Keywords: Annuity, Amortisation, Sinking Fund, Present and Future Value Annuity, Maturity date and Redemption value

Characteristics and Nature of Academic Staff’s User Experiences in Electronic Library Database Utilisation

Abstract Introduction. The use of electronic library databases (e-library databases) by academic staff is accepted globally as contributing immensely-to academic staff research work. However, based on one of the researchers’ experiences as a Subject Librarian as well as context-specific issues that arose from the existing literature, e-library databases are underutilised by academic staff at the University of Jos and similar institutions in North-Central Nigeria. Many previous studies on the use of e-library databases by academic staff in Nigerian universities were centred on the quantitative survey methodology, which lack in-depth perspectives of academics’ experiences. Thus, additional qualitative insights are necessary. Hence, this study aimed to improve our understanding of the personal/individual experiences affecting academic staff e-library database utilisation in universities in North-Central Nigeria, through ethnographic research. Method. The stratified sampling method was used in selecting participants. The researcher employed observation and semi-structured interviews to collect data from 44 academic staff selected from 22 faculties of the Universities and one system librarian from each of the university libraries. A constant comparative approach was used in the analysis of data. Results. The results revealed negative/unsatisfying experiences and a lack of interest in using e-library databases affected academics’ use of the e-library databases. The researcher discovered that online library database use and technology are generally less common to older academics but appear to be more familiar amongst the younger ones. Conclusion. Therefore, the study recommended that Academic Subject Librarians have to consider online library database design strategies to shore up the use rates. The university should also prioritise behavioural change

An ethnographic study of the utilisation of electronic library databases by academic staff in North-Central Nigeria.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.This ethnographic case study is an exploration of the utilisation of electronic library databases by academic staff in North-Central Nigeria. The motivation for this study stemmed from the researcher's experiences as a Subject Librarian as well as context-specific issues that arose from the existing literature. For instance, there was under-utilisation of e-library databases by academic staff at the University of Jos, Plateau State, alongside similar institutions in North-Central Nigeria. Many previous studies on the use of e-library databases by academic staff in Nigerian universities were centred on the quantitative survey methodology. Hence, this study aimed to improve an understanding of the personal/individual experiences, environmental contexts and socio-cultural factors affecting academic staff e-library database utilisation, through ethnographic research. Accordingly, the Symbolic Interactionist Ethnography-SIE underpinned the study. The application of the theory was anchored by the Interpretivist approach, which was supported by the execution of a case study method of research in which academics from the University of Jos, Plateau state and the Federal University of Agriculture, Makurdi, Benue state were targeted. The probabilistic and non-probabilistic sampling procedures were used in selecting participants. Specifically, the purposive and stratified sampling methods were used. The qualitative research approach adopted for the study gave the researcher the opportunity to elicit detailed views of academics' perspectives on the phenomenon through observation, photovoice, semi-structured interviews, and focus group discussions. Also, documents were evaluated for triangulation of results. Data were thematically analysed according to the criteria for trustworthiness, such as credibility, transferability, dependability, and confirmability. A constant comparison approach was used in the analysis of data. The study also compared findings from all sources of data collection and cases focused on in this study. Consequently, the study's findings indicated academics engage with the e-library databases for research from their offices, as the office is their workspace that provides a suitable environment for the academics to engage in research and prepare for lectures. The study's core results revealed academics' leaning toward printed sources of information for teaching and research. The decision could be linked to their human nature, individual differences, and personalities, such as a resistance to change. The results revealed negative/unsatisfying experiences due to several limitations, such as inadequate skills, and library staff assistance in academics' use of online databases as the main reason for low use. Also, the results showed shared experiences with colleagues in the faculty influenced academics' use of e-library databases. The study further discovered a lack of interest in academics' use of online library databases as the main reason for low usage. The study concluded that socio-cultural factors and environmental contexts affect academics' utilisation of e-library databases. Therefore, the study recommends that the university authorities scrupulously comprehend modern technology connected with the organisational culture and encourage academic staff of its value and benefits. There is as well the need for university libraries to develop e-database policies and frequently review and update the policies and practices associated with utilising e-library databases. The university management can do that by establishing interventions to tackle inappropriate e-library database use. Finally, actors in universities must be committed to integrating the socio-cultural work environment as an intended benefit (essential factor) in enhancing e-library database use

Generation of biogas from segregates of municipal solid wastes in Jos, Nigeria

A study was carried out to explore the amount of biogas that could be produced using segregated portions of municipal solid wastes (food residue, leaves, paper and a mixture of the three segregates) in Jos city, Nigeria, as substrates. The segregates were mixed with water and cow dung as inoculums, in the ratio of 3:3:1 and subjected to anaerobic digestion using a laboratory-biogas generation system set at 37oC for a period of 25 days. The initial and final pH values of the substrates were recorded. The amount of biogas generated was measured by the method of downward displacement of water from a measuring cylinder. Total plate and methanogenic bacterial counts were taken prior to, during and after fermentation respectively. The bacteria associated with the wastes were cultured on nutrient agar and modified methanogenic agar medium, enumerated, isolated and then characterized using standard bacteriological techniques. Microbial succession during the fermentation process of biogas production was determined. The results show that all the substrates demonstrated potentials for biogas production with leaves generating the highest volume of biogas. The volumes generated by each segregate were 996cm3, 52cm3, 36cm3 and 24cm3 for leaves, food residue, mixture of segregates and paper respectively. The microorganisms isolated includeStaphylococcus aureus, Streptococcus spp, Escherichia coli, Clostridium spp, Methanococcus spp and Methanobacterium spp. The results on the microbial succession study indicate that Streptococcus spp, Clostridiumspp, Escherichia coli, Methanobacterium spp and Methanococcus spp were the most active organisms involved in the biodigestion/biogas generation process. It can be concluded from the study that municipal solid wastes are a potential energy source for biogas generation that could be optimized at industrial scales