Prevalence of Salmonella Typhi, Staphylococcus aureus and intestinal parasites among male food handlers in Laghouat Province, Algeria

Background: Food-borne diseases are a global public health problem, most especially in developing countries. Food handlers with a low level of  personal hygiene may be colonized or infected by a wide range of enteric pathogenic micro-organisms including intestinal parasites and bacteria.  The aim of this study is to determine the prevalence of Salmonella Typhi, Staphylococcus aureus and intestinal parasites among male food handlers  in Laghouat province, southern Algeria. Methodology: In this cross-sectional study, stool samples and fingernail samples of both hands were collected from 155 randomly selected male  food handlers. Stool specimens were examined by direct wet mount, formalinether concentration, xenic invitro culture and staining methods for  parasitological identification. For bacterial isolation, standard culture media including Hektoen agar, Salmonella-Shigella (SS), Mannitol salt, and  Blood agar plates were used. Conventional biochemical tests were used for identification of S. Typhi and S. aureus. Antimicrobial susceptibility test  (AST) was performed for bacterial isolates by the Kirby-Bauer disk diffusion method. Data analysis was done using Minitab version 19 software, and  Pearson’s Chi-square test was used to determine association between categorical variables. P value < 0.05 was considered statistically significant.   Results: The overall prevalence rate of intestinal parasites among the study subjects was 40% (62/155). Blastocystis spp was the most frequent  parasite isolated (16.8%), followed by Giardia intestinalis (8.4%), Entamoeba histolytica/dispar (7.7%), Entamoeba coli (3.2%), Trichomonas intestinalis  (2.6%) and Endolimax nana (1.3%). Stool cultures revealed 4 (2.6%) positive samples for S. Typhi, and S. aureus was isolated from fingernail contents  of 23 (14.8%) subjects. All S. Typhi isolates were sensitive to imipenem and ciprofloxacin while S. aureus isolates show high sensitivity to  pristinamycin. Hand washing with soap, finger nail status and clinical manifestations were significantly associated with intestinal parasitic infections,  while clinical manifestation was the only factor associated with S. aureus infection. Conclusion: The present study indicates a high prevalence of pathogenic micro-organisms among male food handlers which highlight the important role of food handlers in the spread and transmission of foodborne infections, and thus requires more attention

The importance of aligning managerial characteristics to functional strategy in public sector organisations: An empirical study of Dubai government.

Managerial characteristics have an important influence on strategy implementation. Previous studies have looked at the alignment of managerial characteristics with strategic type and aspects of performance. In all cases, the focus has been on corporate strategy and, predominantly, in private sector organisations. This study combines these objectives and investigates alignment between managerial characteristics, strategy and perceived performance. It focuses on management at the functional level in a public sector setting and demonstrates that classical upper-echelon theory is also relevant when applied at the functional level of management. The Miles and Snow (1978) typology is applied to the functional strategy for Dubai government organisations, to investigate whether functional units pursuing strategies are led by functional managers with dissimilar attributes, and whether the alignment between managerial characteristics and strategy is related to performance of the functional unit. Based on the extant literature, a research model has been developed, which yields two types of hypothesis. Data was collected by means of interviews and surveys to obtain knowledge of strategy types, and demographic and psychological characteristics for the functional managers. Regression techniques have been used for data analysis rendering support for two types of hypothesis. Consequently, this study supports the view that Upper Echelon theory can also apply at the functional level, emphasising the role of the functional managers, at the lower management levels of the organisations, in strategy implementation

Fault diagnosis of power converters in a grid connected photovoltaic system using artificial neural networks

Introduction. The widespread use of photovoltaic systems in various applications has spotlighted the pressing requirement for reliability, efficiency and continuity of service. The main impediment to a more effective implementation has been the reliability of the power converters. Indeed, the presence of faults in power converters that can cause malfunctions in the photovoltaic system, which can reduce its performance. Novelty. This paper presents a technique for diagnosing open circuit failures in the switches (IGBTs) of power converters (DC-DC converters and three-phase inverters) in a grid-connected photovoltaic system. Purpose. To ensure supply continuity, a fault-diagnosis process is required throughout all phases of energy production, transfer, and conversion. Methods. The diagnostic approach is based on artificial neural networks and the extraction of features corresponding to the open circuit fault of the IGBT switch. This approach is based on the Clarke transformation of the three-phase currents of the inverter output as well as the calculation of the average value of these currents to determine the exact angle of the open circuit fault. Results. This method is able to effectively identify and localize single or multiple open circuit faults of the DC-DC converter IGBT switch or the three-phase inverter IGBT switches.Вступ. Широке використання фотоелектричних систем у різних застосуваннях висунуло на перший план нагальні вимоги до надійності, ефективності та безперервності обслуговування. Основною перешкодою для ефективнішого застосування була надійність силових перетворювачів. Справді, наявність несправностей у силових перетворювачах може спричинити збої в роботі фотоелектричної системи, що може знизити її продуктивність. Новизна. У цій статті представлена методика діагностики обриву кола в перемикачах (IGBT) силових перетворювачів (перетворювачів постійного струму та трифазних інверторів) у фотоелектричній системі, підключеній до мережі. Мета. Для забезпечення безперервності постачання потрібен процес діагностики несправностей на всіх етапах виробництва, передачі та перетворення енергії. Методи. Діагностичний підхід заснований на штучних нейронних мережах та вилучення ознак, що відповідають обриву кола IGBT-перемикача. Цей підхід ґрунтується на перетворенні Кларка трифазних струмів на виході інвертора, а т акож розрахунку середнього значення цих струмів для визначення точного кута обриву кола. Результати. Цей метод дозволяє ефективно ідентифікувати та локалізувати одиночні або множинні несправності розімкнутого кола IGBT-перемикача DC-DC перетворювача або IGBT-перемикача трифазного інвертора

Wave propagation in stereo-lithographical (STL) bone replicas at oblique incidence

Comparisons between predictions of a Biot-Allard model allowing for angle-dependent elasticity and angle-and-porosity dependent tortuosity and transmission data obtained at normal incidence on water-saturated replica bones are extended to oblique incidence. The model includes two parameters which are adjusted for best fit at normal incidence. Using the same parameter values, it is found that predictions of the variation of transmitted waveforms with angle through two types of bone replica are in reasonable agreement with data despite the fact that scattering is not included in the theory

Fault diagnosis of power converters in a grid connected photovoltaic system using artificial neural networks

Introduction. The widespread use of photovoltaic systems in various applications has spotlighted the pressing requirement for reliability, efficiency and continuity of service. The main impediment to a more effective implementation has been the reliability of the power converters. Indeed, the presence of faults in power converters that can cause malfunctions in the photovoltaic system, which can reduce its performance. Novelty. This paper presents a technique for diagnosing open circuit failures in the switches (IGBTs) of power converters (DC-DC converters and three-phase inverters) in a grid-connected photovoltaic system. Purpose. To ensure supply continuity, a fault-diagnosis process is required throughout all phases of energy production, transfer, and conversion. Methods. The diagnostic approach is based on artificial neural networks and the extraction of features corresponding to the open circuit fault of the IGBT switch. This approach is based on the Clarke transformation of the three-phase currents of the inverter output as well as the calculation of the average value of these currents to determine the exact angle of the open circuit fault. Results. This method is able to effectively identify and localize single or multiple open circuit faults of the DC-DC converter IGBT switch or the three-phase inverter IGBT switches

Prevalence and risk factors of intestinal protozoan infection among symptomatic and asymptomatic populations in rural and urban areas of southern Algeria

Background: Intestinal parasitic infections are amongst the most common infections worldwide and have been identified as one of the most significant causes of morbidity and mortality among disadvantaged populations. This comparative cross-sectional study was conducted to assess the prevalence of intestinal protozoan infections and to identify the significant risk factors associated with intestinal parasitic infections in Laghouat province, Southern Algeria. Methods: A comparative cross-sectional study was conducted, involving 623 symptomatic and 1654 asymptomatic subjects. Structured questionnaires were used to identify environmental, socio demographic and behavioral factors. Stool specimens were collected and examined using direct wet mount, formalin-ether concentration, xenic in vitro culture and staining methods. Results: A highly significant difference of prevalence was found between symptomatic (82.3%) and asymptomatic subjects (14.9%), with the majority attributable to protozoan infection. The most common species in the symptomatic subjects were Blastocystis spp. (43.8%), E. histolytica/dispar (25.4%) and Giardia intestinalis (14.6%) and more rarely Enterobius vermicularis (02.1%), Teania spp. (0.6%) and Trichuris trichiura (0.2%), while in asymptomatic population Blastocystis spp. (8%), Entamoeba coli (3.3%) and Entamoeba histolytica/dispar (2.5%) were the most common parasites detected with no case of helminth infection. Multivariate log-linear analysis showed that contact with animals was the main risk factor for transmission of these protozoa in both populations. Furthermore, living in rural areas was significantly associated with combined protozoan infection in the asymptomatic population, whereas, in the symptomatic population an increasing trend of protozoan infection was detected in the hot season. In addition, Blastocystis spp. and G. intestinalis infection were found to be associated with host sex and contact with animals across the study period. Conclusions: Based on these results, several strategies are recommended in order to effectively reduce these infections including good animal husbandry practices, health education focused on good personal hygiene practices and adequate sanitation

Non-ambiguous recovery of Biot poroelastic parameters of cellular panels using ultrasonic waves

a b s t r a c t The inverse problem of the recovery of the poroelastic parameters of open-cell soft plastic foam panels is solved by employing transmitted ultrasonic waves (USW) and the Biot-Johnson-Koplik-Champoux-Allard (BJKCA) model. It is shown by constructing the objective functional given by the total square of the difference between predictions from the BJKCA interaction model and experimental data obtained with transmitted USW that the inverse problem is ill-posed, since the functional exhibits several local minima and maxima. In order to solve this problem, which is beyond the capability of most off-the-shelf iterative nonlinear least squares optimization algorithms (such as the Levenberg Marquadt or Nelder-Mead simplex methods), simple strategies are developed. The recovered acoustic parameters are compared with those obtained using simpler interaction models and a method employing asymptotic phase velocity of the transmitted USW. The retrieved elastic moduli are validated by solving an inverse vibration spectroscopy problem with data obtained from beam-like specimens cut from the panels using an equivalent solid elastodynamic model as estimator. The phase velocities are reconstructed using computed, measured resonance frequencies and a time-frequency decomposition of transient waves induced in the beam specimen. These confirm that the elastic parameters recovered using vibration are valid over the frequency range of study

Study of the curative role of "Draas" in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

Sand drifting on road networks in the region of the Lower Algerian Sahara is one of the main problems for the sector. Machines are repeatedly deployed to overcome this phenomenon. The long experience acquired while dealing with the removal of sand from roads pushed us to focus on obstacles called "Draas". The purpose of this study is to perform an optimization of these special protective structures called “Draas”, using a reduced physical model. Model tests were performed in flow channel. The principle of modeling the wind transport using a reduced model is to simulate the wind using a liquid stream while respecting the laws of hydraulic and sedimentological similarity. The results obtained are extrapolated to make a normal size prototype

Self-Maintainable Views Group in P2P Environment

Peer-to-Peer environment is gradually more popular for sharing data for distributed applications. Peer-to-peer makes these applications more reliable, efficient, available and scalable. Also, materialized views which are derived from base relations are often used to speed up query processing and data sharing. In this paper, we are interested in materialized view maintenance in P2P environment; we propose a new approach which uses some characteristics of views in such system. Our maintenance approach consists to create virtual groups of peers. Groups will contain views that sharing maximum of common data sources, then, we will associate at each group a set of auxiliary views which will be stored in a peer chosen by our algorithm, it will be the group center. The auxiliary views set will allow the group to be self-maintainable.  Then, we propose a view maintenance algorithm based on two steps, notification of modifications and computing & sending of view updates. Finally simulation experiments implemented with java, show that both maintenance cost and total message number are reduced using our approach, we compared group maintenance cost in various situations in order to find the optimal conditions that our proposal is more efficient.&nbsp