700 research outputs found
Enteric Diseases of Poultry with Special Attention to Clostridium perfringens
Several enteric disorders affect poultry and cause illness, mortality and
economic losses. The ban on antibiotic growth promoters increased the problem
by allowing intestinal bacteria, influenced by predisposing factors, to
destroy the internal lining of the gut. How do you recognise the problem and
what can be done about it
Factors affecting elementary teachers’ decision to integrate information and communication technologies (ICT) in an Egyptian international school
Integrating Information and Communication Technology (ICT) is a desired educational outcome. Schools invest substantially in technological hardware and software as well as teacher training to encourage ICT integration. However, the results often do not match the investment. The current case study examined the factors that affect elementary teachers’ decision, in an Egyptian international school, to integrate ICT in education with the aim of using the results to inform future ICT related decisions, policies and practices at this particular school. Using a modified form of participatory evaluation (Cousins & Whitmore, 1998; Zukoski & Luluquisen, 2002) and Wagner’s and Kegan’s 4 C’s model(Wagner et al., 2010), the researcher used quantitative and qualitative methods to investigate the conditions, context, competencies, and culture that impact ICT integration at the individual and organizational levels. An online survey was administered to all elementary teachers at school X to examine the current status of the school in terms of the 4Cs. This was followed by a focus group for which low-ICT and high-ICT integration teachers were selected to discuss 1) the current state of the school for ICT integration in terms of the 4Cs; 2) the desired state of the school; and 3) recommendations that would enable the school to bridge the gap between both states. It was expected that the participatory nature of the research would enhance teachers’ ownership of the ICT integration process and outcome. One of the main conclusions in this study is that almost all elementary teachers in school X believe in the importance of ICT integration in the teaching and learning process. Deficiencies in their ICT integration trends are not due to teachers’ perception, rather they are caused by one or more of the factors identified in the four domains, culture, conditions, competencies, and culture such as lack of adequate instructional/pedagogical support or the low quality of some of the professional development sessions that teachers attend. The outcome of this research was a set of recommendations for a realistic, clear, and achievable action plan to enhance the effectiveness of ICT integration in school X. Factors identified to affect elementary teachers’ decision to integrate ICT in education included but were not limited to: training in ICT integration, technical support, pedagogical support, access to technology resources, teachers’ competence in using multiple ICT tools and skills
Efficacy of six disinfection methods against extended-spectrum beta-lactamase (ESBL) producing E. coli on eggshells in vitro
The presence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli on poultry products is an important issue for veterinary and human health due to the zoonotic infection risk for producers and consumers. The present study focuses on testing the efficacy of six different disinfection methods on eggshell samples, aiming to reduce ESBL producing E. coli contamination on the hatching egg. Sterile eggshell cutouts were artificially contaminated with 10(8) cfu/ml CTX-M-1 producing E. coli and used as a carrier model to analyze the efficacy of six disinfection methods. The contaminated samples were separated into two groups; 1) contaminated and disinfected, 2) contaminated and non-disinfected. Six independent disinfection protocols were performed following product specifications and protocols. Each eggshell sample was separately crushed, and the total viable bacterial count was calculated to determine the disinfection efficacy. Five out of six tested methods (formaldehyde gassing, hydrogen peroxide + alcohol spray, essential oils spray, peracetic acid foam, and low energetic electron radiation) demonstrated a reduction or completely eliminated the initial ESBL producing E. coli contamination. One method (essential oils as cold fog) only partly reached the expected efficacy threshold (reduction of >10(2) cfu/ml) and the result differed significantly when compared to the reference method i.e. formaldehyde gassing
Assessment of three alternative methods for bacterial disinfection of hatching eggs in comparison with conventional approach in commercial broiler hatcheries
The disinfection of commercial hatching eggs before incubation is a common strategy to reduce potential vertical transmission of bacterial and fungal infections from the eggshell to one-day-old chicks that may prevail in poultry products and eventually reach the end consumer. The present investigation focuses on the parallel testing and application of four different disinfection methods (conventional and alternative) under commercial hatchery conditions against natural eggshell bacterial contamination. Hatching eggs from two ROSS 308 broiler breeder flocks were selected and divided into six different groups: two groups were not disinfected and served as negative controls, and four were independently disinfected following product specifications and protocols. From each group, a sample of 100 hatching eggs was selected for bacterial re-isolation, utilizing a modified shell rinse method. Colony-forming units (cfu) from the shell rinse suspensions were determined and analyzed to establish cfu values for each tested egg. These values were analyzed to determine the bacterial disinfection capacity of the four disinfection methods under commercial hatchery conditions. The tested methods were hydrogen peroxide + alcohol, peracetic acid, low energy electron beam, and the gold standard in practice: formaldehyde. Among these methods, formaldehyde, peracetic acid, and low energy electron beam showed a significant difference when compared to the non-disinfected groups whereas hydrogen peroxide + alcohol did not. The bacterial disinfection capacity of the tested methods was compared as well to the gold standard method formaldehyde fumigation and only low energy electron beam achieved similar disinfection levels as formaldehyde. According to our data, three methods significantly reduce the bacterial load on the eggshell of hatching eggs under commercial hatching conditions, including potential alternative methods such as low energy electron beam that perform similar to the gold standard in practice
Reflection High-Energy Electron Diffraction Studies of Indium Phosphide (100) and Growth on Indium and Indium Nitride on Silicon (100)
Study of the effects of atomic hydrogen exposure on structure and morphology of semiconductor surfaces is important for fundamental properties and applications. In this dissertation, the electron yield of a hydrogen-cleaned indium phosphide (InP) surface was measured and correlated to the development of the surface morphology, which was monitored by in situ reflection high-energy electron diffraction (RHEED). Atomic hydrogen treatment produced a clean, well-ordered, and (2x4)-reconstructed InP(100) surface. The quantum efficiency, after activation to negative electron affinity, and the secondary electron emission were shown to increase with hydrogen cleaning time. RHEED patterns of low-index InP(100) surface were modified by the step structure and resulted in splitting of the specular beam at the out-of-phase diffraction condition. Quantitative RHEED showed reduction in the average terrace width and a decrease of the adatom-vacancy density with hydrogen exposure. This suggests that atomic hydrogen etching occurs preferentially at terrace edges, and thermal diffusion on the surface causes changes in the terrace edge morphology, which result in the observed decrease in the average terrace width. The results show that the decrease in the surface disorder, measured from the RHEED intensity-to-background ratio, correlated with the increased quantum efficiency.
The growth of group-III metals on Si surfaces has become an attractive area of research because of its scientific importance and great potential in technological applications. In this work, the growth dynamics, structure, and morphology of indium (In) on a vicinal Si(100)-(2×1) surface by femtosecond pulsed laser deposition (fsPLD) were studied using in situ RHEED and ex situ atomic force microscopy. Indium was found to grow on Si(100) by the Stranski-Krastanove mode. At room temperature, the initial growth formed strained two-dimensional (2D) layers in the In(2×1) structure followed by growth of three-dimensional islands. During the 2D growth, the surface diffusion coefficient of deposited In on the In(2×1) layer was estimated to be in the order of 10−14 cm2/s, from recovery of the RHEED intensity. This was attributed to surface diffusion of In clusters by step flow mode. The results suggest that fsPLD of In removed the reconstruction of the Si(100)-(2×1) surface in the early growth and resulted in the initial In(2x1) structure. Next, growth of In on Si(100)-(2×1) was studied at temperature of 350–420°C and showed formation of In(4×3) structure. The growth stages, probed by RHEED intensity relaxation, proceed in a two-step process, formation of small In clusters and surface diffusion to the terrace step edges with activation energy of 1.4±0.2 eV and diffusion rate constant of 1.0±0.1x1011 s −1. The terrace width dynamics and the related surface processes were studied during growth of the In(4×3) phase with increase in film coverage. Finally, the fsPLD was used to grow nitride films of InN on Si(100) substrates. A buffer layer of In was grown on Si(100) by fsPLD prior to growth of InN and different nitridation procedures were used
Cyclocondensation, antimicrobial activity and semi-empirical AM1-MO calculations of benzopyrone derivatives
An efficient synthesis of 7-amino-9-hydroxy-6-oxo-6H-benzo[c]chromene-8-carbonitrile derivatives (2,6) and 4-methyl-2-oxo-2H-chromene-3-carbonitrile (5) via Claisen condensation of 2-hydroxyacetophenones (1,3) with ethyl cyanoacetate in the presence of sodium metal is reported. Reaction of 5 with thiosemicarbazide gave 1-(3-cyano-4-methyl-2-oxoquinolin-1(2H)-yl)thiourea (7). Treatment of 5 with 6,8-dichloro-4-oxo-4H-chromene-3-carboxaldehyde gave 4-(2-(6,8-dichloro-4-oxo-4H-chromen-3-yl)-2-hydroxyethyl)-2-oxo-2H-chromene-3-carbonitrile (9). Further treatment of 5 with ethyl acetate followed by condensation with 6,8-dichloro-3-formylchromone gave 7-((6,8-dichloro-4-oxo-4H-chromen-3-yl)methyleneamino)-9-hydroxy-6H-benzo[c]chromen-6-one (12). Structures of the products were established on the basis of elemental analysis, IR, 1H and 13C NMR, mass spectra and semi-empirical AM1-MO calculations. The antimicrobial activities of the synthesized products were also studied
Sutureless Perceval versus Bioprosthetic Aortic Valve, Single Center Experience
Background: High-risk patients are currently presenting for aortic valve replacement (AVR). Sutureless valves may decrease the operative risk in those patients. The objective of this study was to compare the short-term and one-year follow-up results of the sutureless Perceval valve versus bioprosthetic aortic valve.
Methods: The data of patients who underwent elective AVR with bioprosthesis were collected From March 2012 to March 2017. The patients were divided into two groups; group 1 included the patients who had a sutureless aortic valve (Perceval) (n= 25; 3.57% of total AVR patients), and group 2 included patients who had conventional bioprosthesis (n= 50; 7.1% of total AVR patients).
Results: The median age of patients in group 1 was 67 years (25th- 75th percentiles; 64-71), and in group 2 was 66 years (25th- 75th percentiles: 63 to 69). There is no significant difference in the patients’ comorbidities between the two groups. The median duration of the ischemic time was significantly lower in group 1 (33 (25th- 75th percentiles: 32- 35) vs. 60.5 (58- 66), respectively; p< 0.001). Perceval valve was used more commonly in patients who had minimally invasive AVR (n= 21 (84%) in group 1 vs. 11 (22%) in group 2; p<0.001). Postoperative complications were comparable between both groups. The early paravalvular leak was non-significantly higher in group 1 (12% vs. 2%; p= 0105). The mean postoperative gradient was lower in group 1 (7 (7-9) vs. 10 (8-12) mmHg; p<0.001). The changes in valvular gradient were not significantly different between both groups (p= 0.5). The hospital stay was lower in patients received Perceval valve (Coefficient: -1.3; 95% Cl: -2.3- -0.29; p=0.012)
Conclusion: Sutureless aortic valve (Perceval) is a new surgical technique for AVR, with potential advantages of reducing cross-clamp time and a subsequent reduction in myocardial ischemia, duration of cardiopulmonary bypass, and maintaining satisfactory hemodynamic outcomes through reducing patient prosthesis mismatch. All these advantages could help in decreasing postoperative hospital stay. 
An efficient synthesis of some new isolated and fused 2-oxo-2H-chromene derivatives as antimicrobial and antitumor agents
An efficient synthesis of the biologically active novel systems derived from the reaction of 4-methyl-2-oxo-2H-chromene-3-carbonitrile (1) with sodium hydroxide and/or DMF-DMA and cyclocondensation reactions of 4-[(E)-2-(dimethylamino)ethenyl]-2-oxo-2H-chromene-3-carbonitrile (5) with nitrogen nucleophilic reagents afforded the corresponding 4-iminochromeno[3,4-c]pyridine derivatives (6-14). The structures of the prepared compounds have been proved by elemental analysis, IR, 1H Â and 13C NMR and mass spectra. Significant antitumor activities in planta were observed for some of the prepared compounds
From division to unity: transnational integration and the power of the AfCFTA
While African political leaders have sought to create and
implement various regional integration policies, there has been
slow progress in achieving results due to leadership, economic
and security complexities. Africa is growing at a good pace but
transforming at a slow one. Opening up borders so people and
goods can move has recently become one of the African Union’s
main aims, inspired by the European Union. A continental intratrade
focus is perceived as an initial transformative phase on the
road to complete efficient integration and robust global influence.
In this context, the African continental free trade area (AfCFTA)
has been conceived as a new instrument to tackle the complexity
of integration barriers and remove them.
This policy brief explores the projected outcomes of the
implementation of the AfCFTA and argues that adopting a
transnational regional approach during the implementation stage
will unleash competitiveness leading to realising its full potential.
Against this background, the brief focuses on supporting the
emergence of a regional market that is appealing to investors
and capable of fostering economic growth and job creation. It
also examines how the AfCFTA complements classic regional
integration endeavours.Funded by the European Union. Views and opinions expressed are however those
of the author(s) only and do not necessarily reflect those of the European Union or
the European Education and Culture Executive Agency (EACEA). Neither the European
Union nor EACEA can be held responsible for them
Ecotoxicity effects of oil Water Accommodated Fractions and oil Water Accommodated Fractions + Dispersant on cold environments: Acarita tonsa based bioassays and microbial community dynamics as monitoring tools
224 p.La contaminación por petróleo es un problema importante en los océanos y mares, especialmente en ambientes frÃos y regiones polares, donde los procesos de remediación son más complejos y los ecosistemas son muy vulnerables. Durante un vertido de petróleo diversos factores meteorológicos y el movimiento de las olas favorecen la integración de los hidrocarburos hidrofÃlicos en la columna de agua, siendo el producto resultante la conocida como fracción acomodada del petróleo en el agua (WAF), que suele estar compuesta principalmente, aunque no solo, por hidrocarburos aromáticos policÃclicos (HAPs). Históricamente como forma de remediación ante los vertidos de petróleo se ha utilizado la incorporación de dispersantes quÃmicos que favorecen la degradación del petróleo. Sin embargo, diversos estudios han demostrado que los dispersantes quÃmicos pueden tener efectos adversos sobre los organismos marinos. El objetivo de este proyecto de Tesis doctoral ha sido estimar el posible impacto del WAF de un petróleo nafténico del Atlántico Norte (NNA), con o sin la adición del dispersante quÃmico Finasol OSR52, mediante bioensayos in vivo con copépodos y el estudio de alteraciones en comunidades microbianas. Los bioensayos con el organismo modelo Acartia tonsa demostraron que el NNA WAF fue menos tóxico que los WAFs obtenidos a partir de destilados de fuel oil (IFO 180 y Gasóleo de uso marÃtimo), que mostraron una alta toxicidad a distintos niveles de organización biológica (transcripción génica, reproducción y supervivencia) en los copépodos. Al añadir el dispersante quÃmico el NNA WAF fue más tóxico para los copépodos en términos de alteración de la transcripción génica, la reproducción y la mortalidad. En el caso de las comunidades microbianas, al examinar en condiciones de microcosmos los efectos del NNA WAF en solitario y NNA WAF con dispersante, se pudo observar que el dispersante no favoreció la biodegradación bacteriana de los compuestos procedentes del NNA WAF. Sin embargo, sà alteró las dinámicas de las comunidades microbianas, tanto en la columna de agua como en el sedimento, favoreciendo ciertos taxones. Se observó que las comunidades microbianas que poseÃan desde el inicio bacterias degradadoras de hidrocarburos, debido a un historial de exposición crónico a estos compuestos (legacy effects), fueron el principal impulsor de la degradación de los HAPs en la columna de agua y en los sedimentos. En conclusión, la integración de bioensayos de toxicidad in vivo con copépodos y el estudio de la dinámica de las comunidades microbianas ofrecen una visión amplia de los efectos y respuestas en ecosistemas sensibles que puede causar un escenario de vertido de petróleo y la adición de dispersantes quÃmicos
- …