Search results for: discharging period

Authors: Chang-Bin Ha, Young-Min Ko, Seongjoo Lee, Hyoung-Kyu Song

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In this paper, the signaling scheme using phase shifting is proposed for the improved performance of the Wi-Fi backscatter system. Because the communication in the Wi-Fi backscatter system is based on on-off modulation and impedance modulation by unit of packet, the data rate is very low compared to the conventional wireless systems. Also, because the Wi-Fi backscatter system is based on the RF-powered device, the achievement of high reliability is difficult. In order to increase the low data rate, the proposed scheme transmits information of multiple bits during one packet period. Also, in order to increase the reliability, the proposed scheme shifts the phase of signal in according to the transmitting information. The simulation result shows that the proposed scheme has the improved throughput performance.

Keywords: phase shifting, RF-powered device, Wi-Fi backscatter system, IoT

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Authors: Ammar Asma, Bouafia Nabiha, Ben Cheikh Asma, Ezzi Olfa, Mahjoub Mohamed, Sma Nesrine, Chouchène Imed, Boussarsar Hamadi, Njah Mansour

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Background: Ventilator-associated pneumonia (VAP) is currently recognized as one of the most relevant causes of morbidity and mortality among intensive care unit (ICU) patients worldwide. Identifying modifiable risk factors for VAP could be helpful for future controlled interventional studies aiming at improving prevention of VAP. The purposes of this study were to determine the incidence and risk factors for VAP in in a Tunisian medical ICU. Materials / Methods: A retrospective case-control study design based on the prospective database collected over a 14-month period from September 15th, 2015 through November 15th, 2016 in an 8-bed medical ICU. Patients under ventilation for over 48 h were included. The number of cases was estimated by Epi-info Software with the power of statistical test equal to 90 %. Each case patient was successfully matched to two controls according to the length of mechanical ventilation (MV) before VAP for cases and the total length of MV in controls. VAP in the ICU was defined according to American Thoracic Society; Infectious Diseases Society of America guidelines. Early onset or late-onset VAP were defined whether the infectious process occurred within or after 96 h of ICU admission. Patients’ risk factors, causes of admission, comorbidities and respiratory specimens collected were reviewed. Univariate and multivariate analyses were performed to determine variables associated with VAP with a p-value < 0.05. Results: During the period study, a total of 169 patients under mechanical ventilation were considered, 34 patients (20.11%) developed at least one episode of VAP in the ICU. The incidence rate for VAP was 14.88/1000 ventilation days. Among these cases, 9 (26.5 %) were early-onset VAP and 25 (73.5 %) were late-onset VAP. It was a certain diagnosis in 66.7% of cases. Tracheal aspiration was positive in 80% of cases. Multi-drug resistant Acinerobacter baumanii was the most common species detected in cases; 67.64% (n=23). The rate of mortality out of cases was 88.23% (n= 30). In univariate analysis, the patients with VAP were statistically more likely to suffer from cardiovascular diseases (p=0.035) and prolonged duration of sedation (p=0.009) and tracheostomy (p=0.001), they also had a higher number of re-intubation (p=0.017) and a longer total time of intubation (p=0.012). Multivariate analysis showed that cardiovascular diseases (OR= 4.44; 95% IC= [1.3 - 14]; p=0.016), tracheostomy (OR= 4.2; 95% IC= [1.16 -15.12]; p= 0.028) and prolonged duration of sedation (OR=1.21; 95% IC= [1.07, 1.36]; p=0.002) were independent risk factors for the development of VAP. Conclusion: VAP constitutes a therapeutic challenge in an ICU setting, therefore; strategies that effectively prevent VAP are needed. An infection control-training program intended to all professional heath care in this unit insisting on bundles and elaboration of procedures are planned to reduce effectively incidence rate of VAP.

Keywords: case control study, intensive care unit, risk factors, ventilator associated pneumonia

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Authors: Rocio Murad, Juan Carlos Rivillas, Nury Alejandra Rodriguez, Daniela Roldán

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In Colombia, around 5 million women have suffered forced displacement and all forms of gender-based violence, mostly adolescents and young women, single mothers, or widows with children affected by the war. After the signing of the peace agreements, the department of Antioquia has been one of the most affected by the armed conflict, from a territorial and gender perspective in the period. The objective of the research was to analyze the situation of sexual and reproductive rights in the department of Antioquia from a territorial and gender perspective in the period after the signing of the Peace Agreement. A mixed methodology was developed. The quantitative component conducted a cross-sectional descriptive study of barriers to access to contraceptive methods, safe abortion and gender-based violence based on microdata from the 2015 National Demographic and Health Survey. In the qualitative component, a case study was developed in Dabeiba, a municipality of Antioquia prioritized in order to deepen the experiences before, during and after the armed conflict in sexual and reproductive rights; using three research techniques: Focused observation, Semi-structured interviews, and Documentary review. The results showed that there is a gradient of greater vulnerability to greater effects of the conflict and that the subregion of Urabá Antioqueño, to which Dabeiba belongs, has the highest levels of vulnerability in relation to departmental data. In this subregion, the percentage of women with an unmet need for contraceptive methods (9%), women with unintended pregnancies (31%), of women between 15 and 19 years of age who are already mothers or are pregnant with their first child (32%) and the percentage of women victims of physical violence (42%) and sexual violence (13%) by their partners are significantly higher. Women, particularly rural and indigenous women, were doubly affected due to the existence of violence that is specifically directed at them or that has a greater impact on their life projects. There was evidence of insufficient, fragmented and disjointed social and institutional action in relation to women's rights and the existence of androcentric and patriarchal social imaginaries through which women and the feminine are undervalued. These results provide evidence of violations of sexual and reproductive rights in contexts of armed conflict and make it possible to identify mechanisms to guarantee the re-establishment of the rights of the victims, particularly women and girls. Among the mechanisms evidenced are: working for the elimination of gender stereotypes; supporting the formation and strengthening of women's social organizations; working for the concerted definition and articulated implementation of actions necessary to respond to sexual and reproductive health needs; and working for the recognition of reproductive violence as specific and different from sexual violence in the context of armed conflict. Also, it was evidenced that it is necessary to implement prevention, attention and reparation actions.

Keywords: sexual and reproductive rights, Colombia, armed conflict, violence against women

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Authors: Carlos Roncero-Parra, Alfonso Parreño-Torres, Jorge Mateo Sotos, Alejandro L. Borja

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In this research, different methods based on machine/deep learning algorithms are presented for the classification and diagnosis of patients with mental disorders such as alzheimer. For this purpose, the signals obtained from 32 unipolar electrodes identified by non-invasive EEG were examined, and their basic properties were obtained. More specifically, different well-known machine learning based classifiers have been used, i.e., support vector machine (SVM), Bayesian linear discriminant analysis (BLDA), decision tree (DT), Gaussian Naïve Bayes (GNB), K-nearest neighbor (KNN) and Convolutional Neural Network (CNN). A total of 668 patients from five different hospitals have been studied in the period from 2011 to 2021. The best accuracy is obtained was around 93 % in both ADM and ADA classifications. It can be concluded that such a classification will enable the training of algorithms that can be used to identify and classify different mental disorders with high accuracy.

Keywords: alzheimer, machine learning, deep learning, EEG

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Authors: Khaled Al-Najjar, Ahmad Q. Al-Momani, Ahmed Elnahas, Reda Elsaid

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The research was carried out using records of Awassi sheep bred in drylands at Al-Fjaj Station, Jordan. That aimed to study non-genetic factors affecting milk yield (MK), litter size at birth (LZB); estimate heritability, repeatability, and genetic and phenotypic correlation using SAS and MTDFREML programs. The results were as follows, the average MK and LZB were 92.84 (kg) and 1.16, respectively. MK was highly significantly affected by each parity, age of ewe, year of lambing, and lactation period, while only the year of lambing had a significant effect on LZB. The heritability and repeatability were 0.07 and 0.10 for MK, while it was 0.05 and 0.25 for LZB. The genetic and phenotypic correlations were 0.17 and 0.02 between MK and LZB, respectively. The research concluded that the herd is genetically homozygous and therefore needs to increase genetic variance by introducing LZB-improved rams and selecting females from dams who achieved at least four parties to increase returns in drylands.

Keywords: Awassi sheep, genetic parameters, litter size, milk yield

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Authors: Pranita Shivankar, Devashree Hardas, Prabodhachandra Deshmukh, Arun Suryavanshi

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Bhimbetka Rock Shelters is the UNESCO World Heritage Site located about 45 kilometers south of Bhopal in the state of Madhya Pradesh, India. Rapid changes in land use land cover (LULC) adversely affect the environment. In recent past, significant changes are found in the cultural landscape over a period of time. The objective of the paper was to study the changes in land use land cover (LULC) of Bhimbetka and its peripheral region. For this purpose, the supervised classification was carried out by using satellite images of Landsat and IRS LISS III for the year 2000 and 2013. Use of remote sensing in combination with geographic information system is one of the effective information technology tools to generate land use land cover (LULC) change information.

Keywords: IRS LISS III, Landsat, LULC, UNESCO, World Heritage Site

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Authors: Djehich Mohamed Yousri

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With the advent of social media, political communication scholars have systematically reviewed theories and empirical findings that revolve around media use and democracy. It is interesting that around the same time period, there has been a trend towards revitalization of political populism in different latitudes around the world. This wide-ranging populist movement has expanded regardless of whether these political systems are established democracies, emerging democracies, or societies mired in endangered political contexts. This article serves as an introductory piece to a special issue on populism. First, it highlights the ways in which "populism", as an ancient phenomenon, has transmigrated into the political sphere in the age of social media. Second, the article seeks to better define the populist context and how it has evolved in today's hybrid media society. Finally, this introduction also lays the groundwork for six data-driven theoretical core papers that cover many of the important issues revolving around the phenomenon of populism today.

Keywords: democracy, facebook, populism, social media, twitter

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Authors: Wesam Mohamed Abdel Khalek Ibrahim

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This paper examines the use of metaphors in Arabic political news discourse, focusing particularly on the headlines of the news articles relating to the Egyptian political situation in the period from June 2012 to October 2013. Metaphors are skilfully manipulated in the headlines to influence the public stance towards several events and entities including Egypt, Muslim Brotherhood (MB), Morsi, the June 30th uprising, Al-Sisi and the Armed Forces. The findings reveal that Arabic political news discourse shares basic features with its English counterpart, namely the use of metaphors as persuasive strategies and the presence of certain target domains. Insights gained from this study feed back into the conceptual metaphor theory by providing further evidence to the universality of metaphors.

Keywords: conceptual metaphor theory, political discourse, news discourse, Egyptian political situation

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Authors: Chougrani Fadela, Cheriguene Abderrahim

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Fifty three strains of thermophilic and mesophilic lactic acid bacteria were isolated from the ewe’s milk. Identification reveals the presence of nineteen strains (36%) of Lactobacillus sp., seventeen strains (32%) of Lactococcus sp., nine strains (17%) of Streptococcus thermophilus and eight strains (15%) of Leuconostoc sp. The strains were characterized for their technological properties. A high diversity of properties among the studied strains was demonstrated. On the basis of technological characteristics, two strains (Lactobacillus bulgaricus and Streptococcus thermophilus) were screened with respect to their acid and flavour production for the preparation of a natural yogurt and compared to a commercial starter cultures. Sensorial analyses revealed that the product manufactured on the basis of the isolated strains have a cohesiveness and adhesiveness corresponding to standard products. The pH and the acidity recorded are also within accepted levels during all the period of conservation.

Keywords: Lactobacillus bulgaricus, Streptococcus thermophilus, yoghurt, cohesiveness, adhesiveness, Algerian ewe’s milk

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Authors: J. Winkler, S. Chovancová

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The article deals with the relation between rainfall in selected months and subsequent weed infestation of spring barley. The field experiment was performed at Mendel University agricultural enterprise in Žabčice, Czech Republic. Weed infestation was measured in spring barley vegetation in years 2004 to 2012. Barley was grown in three tillage variants: conventional tillage technology (CT), minimization tillage technology (MT), and no tillage (NT). Precipitation was recorded in one-day intervals. Monthly precipitation was calculated from the measured values in the months of October through to April. The technique of canonical correspondence analysis was applied for further statistical processing. 41 different species of weeds were found in the course of the 9-year monitoring period. The results clearly show that precipitation affects the incidence of most weed species in the selected months, but acts differently in the monitored variants of tillage technologies.

Keywords: weeds, precipitation, tillage, weed infestation forecast

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Authors: S. Bennoud, S. Hocine, H. Slme

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Developments in turbine cooling technology play an important role in increasing the thermal efficiency and the power output of recent gas turbines, in particular the turbojets. Advanced turbojets operate at high temperatures to improve thermal efficiency and power output. These temperatures are far above the permissible metal temperatures. Therefore, there is a critical need to cool the blades in order to give theirs a maximum life period for safe operation. The focused objective of this work is to calculate the turbojet performances, as well as the calculation of turbine blades cooling. The developed application able the calculation of turbojet performances to different altitudes in order to find a point of optimal use making possible to maintain the turbine blades at an acceptable maximum temperature and to limit the local variations in temperatures in order to guarantee their integrity during all the lifespan of the engine.

Keywords: brayton cycle, turbine blades cooling, turbojet cycle, turbojet performances

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Authors: Abir Soltani, Moez Amri, Jouda Mediouni Ben Jemâa

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In North Africa, the chickpea leafminer Liriomyza cicerina (Rondani) (Diptera: Agromizidae) is one of the major damaging pests affecting both spring and winter-planted chickpea. Damage is caused by the larvae which feed in the leaf mesophyll tissue, resulting in desiccation and premature leaf fall that can cause severe yield losses. In the present work, the distribution and the seasonal phenology of L. cicerina were studied on two chickpea varieties; a winter variety Beja 1 which is the most cultivated variety in Tunisia and a spring-sown variety Amdoun 1. The experiment was conducted during the cropping season 2015-2016. In the experimental research station Oued Beja, in the Beja region (36°44’N; 9°13’E). To determine the distribution and seasonal phenology of L. cicerina in both studied varieties Beja 1 and Amdoun 1, respectively 100 leave samples (50 from the top and 50 from the base) were collected from 10 chickpea plants randomly chosen from each field. The sampling was done during three development stages (i) 20-25 days before flowering (BFL), (ii) at flowering (FL) and (ii) at pod setting stage (PS). For each plant, leaves were checked from the base till the upper ones for the insect infestation progress into the plant in correlation with chickpea growth Stages. Fly adult populations were monitored using 8 yellow sticky traps together with weekly leaves sampling in each field. The traps were placed 70 cm above ground. Trap catches were collected once a week over the cropping season period. Results showed that L. cicerina distribution varied among both studied chickpea varieties and crop development stage all with seasonal phenology. For the winter chickpea variety Beja 1, infestation levels of 2%, 10.3% and 20.3% were recorded on the bases plant part for BFL, FL and PS stages respectively against 0%, 8.1% and 45.8% recorded for the upper plant part leaves for the same stages respectively. For the spring-sown variety Amdoun 1 the infestation level reached 71.5% during flowering stage. Population dynamic study revealed that for Beja 1 variety, L. cicerina accomplished three annual generations over the cropping season period with the third one being the most important with a capture level of 85 adult/trap by mid-May against a capture level of 139 adult/trap at the end May recorded for cv. Amdoun 1. Also, results showed that L. cicerina field infestation dispersal depends on the field part and on the crop growth stage. The border areas plants were more infested than the plants placed inside the plots. For cv. Beja 1, border areas infestations were 11%, 28% and 91.2% for BFL, FL and PS stages respectively, against 2%, 10.73% and 69.2% recorded on the on the inside plot plants during the for the same growth stages respectively. For the cv. Amdoun1 infestation level of 90% was observed on the border plants at FL and PS stages against an infestation level less than 65% recorded inside the plot.

Keywords: leaf miner, liriomyza cicerina, chickpea, distribution, seasonal phenology, Tunisia

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Authors: Aleksander Veraksa, Alla Tvardovskaya, Margarita Gavrilova, Vera Yakupova, Martin Musálek

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Considering the current agreement on the significance of executive functions, there is growing interest in determining factors that contribute to the development of these skills, especially during the preschool period. Although multiple studies have been focusing on links between physical activity, physical fitness and executive functions, this topic was more investigated in schoolchildren and adults than in preschoolers. The aim of the current study was to identify different levels of physical fitness among pre-schoolers, followed by an analysis of differences in their executive functions. Participants were 261 5-6-years old children. Inhibitory control and working memory were positively linked with physical fitness. Cognitive flexibility was not associated with physical fitness. The research findings are considered from neuropsychological grounds, Jean Piaget's theory of cognitive development, and the cultural-historical approach.

Keywords: cognitive flexibility, inhibitory control, physical activity, physical fitness, working memory.

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Authors: A. O. Boyo, A. T. Akinwunmi

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The effect of extracting solvent and adjustment of pHs on the stability of Terminalia catappa L. dye-sensitized solar cell was investigated. We introduced ZnO as an alternative to TiO2 in the dye sensitized solar cells (DSSCs) due to its band gap similar to TiO2, higher electron mobility, and flexible procedures of preparations. Dye-sensitized solar cells (DSSCs) based on Terminalia catappa L. was extracted in water (A), ethanol (B) and the mixture of ethanol and water in the ratio 1:1by volume (C). The best performance Solar cells sensitized was from extracts A and achieved up to Jsc 1.51 mAcm−2, Voc 0.75V, FF 0.88 and η 0.63%. We notice that as pHs decreases there is the increase in DSSC efficiency. There is Long period stability in efficiency of the cells prepared using A than in C and a fair stability in efficiency of B cell. The results obtained with extracts B and C confirmed that Ethanol with water could not be considered as a suitable solvent for the extraction of natural dye.

Keywords: zinc oxide, dye-sensitized solar cell, terminalia catappa L., TiO2

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Authors: Douglas E. Mainhart, Alejandro Fierro-Cabo, Bradley Christoffersen, Charlotte Reemts

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Semi-arid ecosystems across the globe have faced land conversion for agriculture and resource extraction activities, posing a threat to the important ecosystem services they provide. Revegetation-centered restoration efforts in these regions face low success rates due to limited soil water availability and high temperatures leading to elevated seedling mortality after planting. Typical methods to alleviate these stresses require costly post-planting interventions aimed at improving soil moisture status. We set out to evaluate the efficacy of applying in-nursery treatments to address transplant shock. Four native Tamaulipan thornscrub species were compared. Three treatments were applied: elevated CO2, drought hardening (four-week exposure each), and antitranspirant foliar spray (the day prior to planting). Our goal was to answer two primary questions: (1) Do treatments improve survival and growth of seedlings in the early period post-planting? (2) If so, what underlying physiological changes are associated with this improved performance? To this end, we measured leaf gas exchange (stomatal conductance, light saturated photosynthetic rate, water use efficiency), leaf morphology (specific leaf area), and osmolality before and upon the conclusion of treatments. A subset of seedlings from all treatments have been planted, which will be monitored in coming months for in-field survival and growth.First month field survival for all treatment groups were high due to ample rainfall following planting (>85%). Growth data was unreliable due to high herbivory (68% of all sampled plants). While elevated CO2 had infrequent or no detectable influence on all aspects of leaf gas exchange, drought hardening reduced stomatal conductance in three of the four species measured without negatively impacting photosynthesis. Both CO2 and drought hardening elevated leaf osmolality in two species. Antitranspirant application significantly reduced conductance in all species for up to four days and reduced photosynthesis in two species. Antitranspirants also increased the variability of water use efficiency compared to controls. Collectively, these results suggest that antitranspirants and drought hardening are viable treatments for reducing short-term water loss during the transplant shock period. Elevated CO2, while not effective at reducing water loss, may be useful for promoting more favorable water status via osmotic adjustment. These practices could improve restoration outcomes in Tamaulipan thornscrub and other semi-arid systems. Further research should focus on evaluating combinations of these treatments and their species-specific viability.

Keywords: conservation, drought conditioning, semi-arid restoration, plant physiology

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Authors: Abdul Rofiq Badril Rizal M. Z.

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This case study examines the experiences of four beginning teachers currently working in New South Wales secondary schools. Data were collected from semi-structured interviews conducted one on one over the period of one month. The data were coded with findings reported through key areas of discovery, which linked to the research presented in the literature review. The participants involved in the case study all reported positive experiences with mentoring, though none were given the opportunity to take part in a formal mentoring program, and all the mentors offered their time voluntarily. The mentoring took different forms, but the support most valued by the participants was the emotional and curriculum related supported received. All participants wished they had greater access to mentoring and felt it would have benefits for most beginning teachers. The study highlights ongoing issues around the lack of access to mentoring, which could be due to factors such as funding, time and training.

Keywords: mentor, mentee, pre-service teacher, beginning teacher

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Authors: Benjamin Osei Tutu, Sharon Annison

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On 21^st November, 2016, an outbreak of foodborne illness occurred after a buffet lunch served during a stakeholders’ consultation meeting held in Accra. An investigation was conducted to characterise the affected people, determine the etiologic food, the source of contamination and the etiologic agent and to implement appropriate public health measures to prevent future occurrences. A retrospective cohort study was conducted via telephone interviews, using a structured questionnaire developed from the buffet menu. A case was defined as any person suffering from symptoms of foodborne illness e.g. diarrhoea and/or abdominal cramps after eating food served during the stakeholder consultation meeting in Accra on 21^st November, 2016. The exposure status of all the members of the cohort was assessed by taking the food history of each respondent during the telephone interview. The data obtained was analysed using Epi Info 7. An environmental risk assessment was conducted to ascertain the source of the food contamination. Risks of foodborne infection from the foods eaten were determined using attack rates and odds ratios. Data was obtained from 54 people who consumed food served during the stakeholders’ meeting. Out of this population, 44 people reported with symptoms of food poisoning representing 81.45% (overall attack rate). The peak incubation period was seven hours with a minimum and maximum incubation periods of four and 17 hours, respectively. The commonly reported symptoms were diarrhoea (97.73%, 43/44), vomiting (84.09%, 37/44) and abdominal cramps (75.00%, 33/44). From the incubation period, duration of illness and the symptoms, toxin-mediated food poisoning was suspected. The environmental risk assessment of the implicated catering facility indicated a lack of time/temperature control, inadequate knowledge on food safety among workers and sanitation issues. Limited number of food samples was received for microbiological analysis. Multivariate analysis indicated that illness was significantly associated with the consumption of the snacks served (OR 14.78, P < 0.001). No stool and blood or samples of etiologic food were available for organism isolation; however, the suspected etiologic agent was Staphylococcus aureus or Clostridium perfringens. The outbreak could probably be due to the consumption of unwholesome snack (tuna sandwich or chicken. The contamination and/or growth of the etiologic agent in the snack may be due to the breakdown in cleanliness, time/temperature control and good food handling practices. Training of food handlers in basic food hygiene and safety is recommended.

Keywords: Accra, buffet, conference, C. perfringens, cohort study, food poisoning, gastroenteritis, office workers, Staphylococcus aureus

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Authors: Thomas Chinwe Urama, Patrick Oseloka Ezepue, Peters Chimezie Nnanwa

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This paper investigates the universal financial dynamics in two dominant stock markets in Sub-Saharan Africa, through an in-depth analysis of the cross-correlation matrix of price returns in Nigerian Stock Market (NSM) and Johannesburg Stock Exchange (JSE), for the period 2009 to 2013. The strength of correlations between stocks is known to be higher in JSE than that of the NSM. Particularly important for modelling Nigerian derivatives in the future, the interactions of other stocks with the oil sector are weak, whereas the banking sector has strong positive interactions with the other sectors in the stock exchange. For the JSE, it is the oil sector and beverages that have greater sectorial correlations, instead of the banks which have the weaker correlation with other sectors in the stock exchange.

Keywords: random matrix theory, cross-correlations, emerging markets, option pricing, eigenvalues eigenvectors, inverse participation ratios and implied volatility

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Authors: Fabien Candau, Florian Lafferrere

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This article analyses how an emission policy for vessels (named California’s Ocean-Going Vessel Fuel Rule) was implemented in 2009 in California impacts trade and marine biodiversity. By studying the decrease in emission levels anticipated by the policy, we measure not only the consequences for port activities but also for one of the most important marine ecosystems of the California Coast: the Kelp forests. Using the Difference in Difference (DiD) approach at the Californian ports level, we find that this policy has led to a significant decrease in trade volume during this period. Therefore, we find a positive and significant effect of shipping policy on kelp canopy and biomass growth by controlling the specific climatic and environmental characteristics of California coastal areas.

Keywords: international trade, shipping, marine biodiversity, emission control area

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Authors: Nicole Kalemba, Fernando Campa-Planas, Ana-Beatriz Hernández-Lara, Maria Victória Sánchez-Rebull

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The purpose of this paper is to determine the effects of service quality on US airlines’ economic performance. In order to cover this goal, it has been considered four different indexes of service quality in the air transportation industry, and also two indicators of economic performance, revenues and return on investment (ROI). Data from American airline companies over a period that covers from 2006 to 2013 have been used in order to determine if airlines’ profitability increases when service quality improves. Considering the effects on airlines’ profitability, the results confirm the positive and significant influence of service quality on the ROI of the companies in our study. Meanwhile, a non-significant effect was found for airline revenues related to quality. No previous research in this area has been done and these findings could encourage airline companies to invest in quality as far as this policy can have a return on their profitability.

Keywords: airlines, economic performance, key performance indicators, quality

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Authors: Manely Ansary Mood, Farzaneh Aziizi, Mahmoud Akbarian

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This investigation included 130 cats diagnosed with FIP (Feb 2021-March 2022) in Iran, 74 with effusive FIP, and 56 with non-effusive FIP. The patients' initial dosage regime consisted of a subcutaneous injection of GS-441524 was 6-15mg/kg-every 24h (based on the wet or ocular and neurologic signs). The minimum treatment period was twelve weeks, extended in animals that still had abnormal lab values, clinical signs, and sonographic findings. The outcomes of the 130 cats that completed the duration of treatment (14 died, 116 cured) were checked and recorded. Clinical, sonographic, and laboratory responses were checked and compared on days 28, 56, and 83 of treatment. 2 of the 116 cured cats relapsed within observation days. At the time of this publication (May 2022), 114 of the studied patients remained healthy. We could conclude that GS-441524 appears to be an effective option for FIP treatment, and also, to the base of our knowledge, this is the first report for group treatment of infected cats of FIP with GS-441524 in Iran.

Keywords: FIP, cat, GS-441524, treatment

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Authors: Hariti Rafika, Fekih Malika, Saighi Mohamed

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During the period storage of liquefied natural gas, stability is necessarily affected by natural convection along the walls of the tank with thermal insulation is not perfectly efficient. In this paper, we present the numerical simulation of heat transfert by natural convection double diffusion,in unsteady laminar regime in a storage tank. The storage tank contains a liquefied natural gas (LNG) in its gaseous phase. Fluent, a commercial CFD package, based on the numerical finite volume method, is used to simulate the flow. The gas is just on the surface of the liquid phase. This numerical simulation allowed us to determine the temperature profiles, the stream function, the velocity vectors and the variation of the heat flux density in the vapor phase in the LNG storage tank volume. The results obtained for a general configuration, by numerical simulation were compared to those found in the literature.

Keywords: numerical simulation, natural convection, heat gains, storage tank, liquefied natural gas

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Authors: Mohammad Lemar Zalmai, Osman Hurol Turkakin, Cemil Akcay, Ekrem Manisali

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In public construction projects, determining the contract period in the award phase is one of the most important factors. The contract period establishes the baseline for creating the cash flow curve and progress payment planning in the post-award phase. If overestimated, project duration causes losses for both the owner and the contractor. Therefore, it is essential to base construction project duration on reliable forecasting. In Turkey, schedules are usually built using the bar chart (Gantt) schedule, especially for governmental construction agencies. The usage of these schedules is limited for bidding purposes. Although the bar-chart schedule is useful in some cases, it lacks logical connections between activities; it would be harder to obtain the activities that have more effects than others on the project's total duration, especially in large complex projects. In this study, a construction schedule is prepared with Critical Path Method (CPM) that addresses the above-mentioned discrepancies. CPM is a simple and effective method that displays project time and critical paths, showing results of forward and backward calculations with considering the logic relationships between activities; it is a powerful tool for planning and managing all kinds of construction projects and is a very convenient method for the construction industry. CPM provides a much more useful and precise approach than traditional bar-chart diagrams that form the basis of construction planning and control. CPM has two main application utilities in the construction field; the first one is obtaining project duration, which is called an as-planned schedule that includes as-planned activity durations with relationships between subsequent activities. Another utility is during the project execution; each activity is tracked, and their durations are recorded in order to obtain as-built schedule, which is named as a black box of the project. The latter is more useful for delay analysis, and conflict resolutions. These features of CPM have been popular around the world. However, it has not been yet extensively used in Turkey. In this study, a real construction project is investigated as a case study; CPM-based scheduling is used for establishing both of as-built and as-planned schedules. Problems that emerged during the construction phase are identified and categorized. Subsequently, solutions are suggested. Two scenarios were considered. In the first scenario, project progress was monitored based as CPM was used to track and manage progress; this was carried out based on real-time data. In the second scenario, project progress was supposedly tracked based on the assumption that the Gantt chart was used. The S-curves of the two scenarios are plotted and interpreted. Comparing the results, possible faults of the latter scenario are highlighted, and solutions are suggested. The importance of CPM implementation has been emphasized and it has been proposed to make it mandatory for preparation of construction schedule based on CPM for public construction projects contracts.

Keywords: as-built, case-study, critical path method, Turkish government sector projects

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Authors: Chupicai Manuel

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The purpose of this article is to examine the political economy and history of internal displacement, migration and human security in Zimbabwe from 1800 to present day. The article gives a timeline of major internal displacement, migration trends that took place in Zimbabwe before colonialism, through the colonial period up to the present day and examines the human security context of such periods. In view of the above, a political economy analysis will be employed to examine the different factors that promoted internal displacement and human movements from 1800 to the present day and explore the architecture of human security in Zimbabwe. The ultimate goal of this literature review is to provide a longitudinal analysis of internal displacement, migration and human security regimes that existed in Zimbabwe with the view of promoting social cohesion and nation building.

Keywords: human security, internal displacement, migration, political economy

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Authors: Eldah Ephraim Buba, Amina Bata Zoaka, Aishatu Ibrahim

Abstract:

This study appraised maintenance practices in selected tourist attractions in Bauchi state, Nigeria. Four tourist attractions were used for the research. Checklists were used to assess operations and repairs maintenance practices in the different attractions. The study carried out personal assessment thrice in six months without prior knowledge of the staff in charge for operational maintenance. Records of repairs maintenance from the attractions maintenance unit for a period of ten years were assessed using the checklists. The findings of the study show that operations maintenance was not adequately carried out in the four tourists attractions. Repairs maintenance was carried out in Yankari game reserve and safari, but repairs maintenance was poor in the other three attractions. The study therefore, recommends that adequate maintenance should be practiced in tourist attractions to expand the lifespan of the facilities and also encourage tourist patronage.

Keywords: appraisal, maintenance, practices, tourist attraction

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Authors: Karrar Raoof Kareem Kamoona, Enas Fathi Taher AlHares, Zeynep Isik

Abstract:

The various disciplines in the construction industry and the co-existence of the people in the various disciplines are what builds well-developed, closely-knit interpersonal skills at various hierarchical levels thus leading to a varied way of leadership. The varied decision making aspects during the lifecycle of a project include: autocratic, participatory and last but not least, free-rein. We can classify some of the decision makers in the construction industry in a hierarchical manner as follows: project executive, project manager, superintendent, office engineer and finally the field engineer. This survey looked at how decisions are made during the construction period by the key stakeholders in the project. From the paper it is evident that the three decision making aspects can be used at different times or at times together in order to bring out the best leadership decision. A blend of different leadership styles should be used to enhance the success rate during the project lifecycle.

Keywords: leadership style, construction, decision-making, built environment

Procedia PDF Downloads 359

Authors: Ali Zefeiti

Abstract:

There has always been a debate on critical versus pragmatic approach to learning English. Different elements of teaching take different shapes in the two approaches. This study concerns itself with the students who are the main pillar of the teaching/learning operation. Students have always been placed into classrooms to learn what the curricula of different courses offer. There is little room for students to state their own learning needs as they often have to conform with the group requirement. This study focuses on an extra-curricular activity students did alongside their mainstream learning. The students come from different colleges and different EAP courses. They are united by their passion for the task and learning many things along the way. The data are collected through interviews and students' journals. The study was concerned with the effect of this extra-curricular activity on students' main learning trajectory. The students were engaged in the task of film production over the period of their English Language course. The findings show that students are able to set their own agenda for learning and have actually had a lot of skills and vocabulary to take to class.

Keywords: critical EAP, pragmatic EAP, self-directed learning, teaching methods

Procedia PDF Downloads 455

Authors: G. Bruno, A. Ciavarella, N. Linciano

Abstract:

The proportion of women in boardroom has traditionally been low around the world. Over the last decades, several jurisdictions opted for active intervention, which triggered a tangible progress in female representation. In Europe, many countries have implemented boardroom diversity policies in the form of legal quotas (Norway, Italy, France, Germany) or governance code amendments (United Kingdom, Finland). Policy actions rest, among other things, on the assumption that gender balanced boards result in improved corporate governance and performance. The investigation of the relationship between female boardroom representation and firm value is therefore key on policy grounds. The evidence gathered so far, however, has not produced conclusive results also because empirical studies on the impact of voluntary female board representation had to tackle with endogeneity, due to either differences in unobservable characteristics across firms that may affect their gender policies and governance choices, or potential reverse causality. In this paper, we study the relationship between the presence of female directors and corporate performance in Italy, where the Law 120/2011 envisaging mandatory quotas has introduced an exogenous shock in board composition which may enable to overcome reverse causality. Our sample comprises Italian firms listed on the Italian Stock Exchange and the members of their board of directors over the period 2008-2016. The study relies on two different databases, both drawn from CONSOB, referring respectively to directors and companies’ characteristics. On methodological grounds, information on directors is treated at the individual level, by matching each company with its directors every year. This allows identifying all time-invariant, possibly correlated, elements of latent heterogeneity that vary across firms and board members, such as the firm immaterial assets and the directors’ skills and commitment. Moreover, we estimate dynamic panel data specifications, so accommodating non-instantaneous adjustments of firm performance and gender diversity to institutional and economic changes. In all cases, robust inference is carried out taking into account the bidimensional clustering of observations over companies and over directors. The study shows the existence of a U-shaped impact of the percentage of women in the boardroom on profitability, as measured by Return On Equity (ROE) and Return On Assets. Female representation yields a positive impact when it exceeds a certain threshold, ranging between about 18% and 21% of the board members, depending on the specification. Given the average board size, i.e., around ten members over the time period considered, this would imply that a significant effect of gender diversity on corporate performance starts to emerge when at least two women hold a seat. This evidence supports the idea underpinning the critical mass theory, i.e., the hypothesis that women may influence.

Keywords: gender diversity, quotas, firms performance, corporate governance

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Authors: Hasan G. Elmazoghi, Aisha I. Alzayani, Lubna S. Bentaher

Abstract:

Rainfall is a highly non-linear phenomena, which requires application of powerful supervised data mining techniques for its accurate prediction. In this study the Artificial Neural Network (ANN) technique is used to predict the mean monthly historical rainfall data collected from BENINA station in Benghazi for 31 years, the period of “1977-2006” and the results are compared against the observed values. The specific objective to achieve this goal was to determine the best combination of weather variables to be used as inputs for the ANN model. Several statistical parameters were calculated and an uncertainty analysis for the results is also presented. The best ANN model is then applied to the data of one year (2007) as a case study in order to evaluate the performance of the model. Simulation results reveal that application of ANN technique is promising and can provide reliable estimates of rainfall.

Keywords: neural networks, rainfall, prediction, climatic variables

Procedia PDF Downloads 488

Authors: Wen Liang Chang

Abstract:

In this study, the optimal replacement time and number of preventive maintenance (PM) actions were investigated for a second-hand device. Suppose that a user intends to use a second-hand device for manufacturing products, and that the device is replaced with a new one. Any device failure is rectified through minimal repair, thereby incurring a fixed repair cost to the user. If the new device fails within the FRW period, minimal repair is performed at no cost to the user. After the FRW expires, a failed device is repaired and the cost of repair is incurred by the user. In this study, two profit models were developed, and the optimal replacement time and number of PM actions were determined to maximize profits. Finally, the influence of the optimal replacement time and number of PM actions were elaborated on, using numerical examples.

Keywords: second-hand device, preventive maintenance, replacement time, device failure

Procedia PDF Downloads 468