CO2 Concentration and Occupants’ Symptoms in Naturally Ventilated Schools in Mediterranean Climate

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO2 concentration was measured in two di erent periods, winter and midseason, to study the impact of the di erent levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and e ects on their health. The mean n50 values are about 7 h-1, whereas the average CO2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed

Дослідження ефективності інтеграції програмних засобів захисту з ОС Windows XP/2000/NT на різних рівнях мережної архітектури

Проаналізовано мережну архітектуру ОС Windows XP/2000/NT. Визначено можливості інтеграції (встроювання) програмних засобів захисту на різних рівнях мережної архітектури. Порівняно ефективність варіантів їх реалізації за допомогою механізмів, які надає ОС Windows XP/2000/NT. Наведено вимоги до програмного засобу захисту та рекомендовані рівні його реалізації. Запропоновано структуру та варіант реалізації програмного засобу захисту.Windows XP/2000/NT network architecture is analyzed. The opportunities of security software integration (embedding) at different network architecture levels are determined. The comparison of the effectiveness of their realization variants with the help of different mechanisms which gives Windows XP/2000/NT is done. The requirements to security software and recommended levels of their realization are given. The structure and a variant of security software realization is offered

The Elusive Antitrust Standard on Bundling in Europe and in the United States in the Aftermath of the Microsoft Cases

Allegations of anticompetitive tying and bundling were significant parts of the antitrust cases against Microsoft in the United States and the European Union. The facts are well known. Starting with the integration of MS-DOS to Windows and the introduction of Windows XP, Microsoft has progressively produced and added to the Windows operating system a number of applications, such as its Web browser, Internet Explorer (which was included in Windows 95 in 1995), and Windows Media Player (WMP), which was integrated to Windows ME in 2000. Microsoft's policy of integrating new functionalities to the Windows operating system has been challenged by both the U.S. and the European antitrust authorities

Vocabulario básico infantil español-amazige [Recurso electrónico]

Características del sistema: PC-Windows 98 / Me / 2000 / XPTit. tomado de la etiqueta del disc

Natural ventilation for the prevention of airborne contagion.

BACKGROUND: Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. METHODS AND FINDINGS: The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. CONCLUSIONS: Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion