Credibility of Design Procedures

Theory of structural reliability enables comprehensive analysis of structural elements with respect to various limit states, and provides valuable insights into the methodology of applied standards. In addition to reliability analysis of the structural element, a new concept of the credibility of theoretical models used to calculate the design value of basic variables is introduced. The presented example of structural verification for limit states of cracking shows that the credibility of commonly applied formulas and reliability of a reinforced concrete slab have a great scatter and are in some cases inadequate

Reliability of Concrete Elements Designed for Alternative Load Combinations Provided in Eurocodes

The basic European standard for design of buildings and other engineering works, EN 1990 "Basis of structural design", provides alternative design procedures, for which national choice is allowed. One of the most important questions concerns three fundamental combinations of actions for persistent and transient design situations in the Ultimate limit states. Simple examples of reinforced concrete elements show, that the alternative load combinations may lead to considerably different reliability levels. Probabilistic methods of structural reliability theory are used to identify characteristic features of each combination and to formulate recommendations. However, further calibration studies are urgently needed in order to prepare National annexes to EN 1990 on time

Target reliability levels in Eurocodes and ISO standards

TARGET RELIABILITY LEVELS IN EUROCODES AND ISO STANDARDS. M. HOLICKÝ, J. MARKOVÁ, M. SÝKORA (Czech Technical University, Prague, Klokner Institute)The target reliability levels recommended in national and international documents vary within a broad range, while the reference to relevant costs and failure consequences is vague only. In some documents the target reliability index is indicated for one or two reference periods (1 year, 50 years or life-time) without providing appropriate links to the design working life. This contribution attempts to clarify the relationship between the target reliability levels, costs of safety measures, failure consequences, reference periods and the design working life. For ultimate limit states of common buildings and bridges (RC2), it is recommended to consider reliability index of 3.8 for a reference period equal to the design working life (50 years for buildings, 100 for bridges).= Рассматриваются условные уровни надежности, рекомендованные в национальных и международных документах. Показано, что эти уровни варьируются в широком диапазоне, в то время как ссылки на соответствующие затраты и последовательность отказов недостаточно изучена. В некоторых документах индекс целевой надежности определяется для одного или двух базовых периодов (1 год, 50 лет или в течение всего жизненного цикла) без предоставления соответствующих ссылок на проекты. В данной работе делается попытка прояснить отношения между уровнями целевой надежности, затратами на обеспечение безопасности, последовательностью отказов, базовыми периодами и сроком эксплуатации. Для предельных уровней состояния общественных зданий и мостов (RC2) рекомендовано использовать целевой индекс 3.8 для периода, равного проектному сроку службы: 50 лет – для зданий,100 лет – для мостов

Target reliability levels in Eurocodes and ISO standards

TARGET RELIABILITY LEVELS IN EUROCODES AND ISO STANDARDS. M. HOLICKÝ, J. MARKOVÁ, M. SÝKORA (Czech Technical University, Prague, Klokner Institute)The target reliability levels recommended in national and international documents vary within a broad range, while the reference to relevant costs and failure consequences is vague only. In some documents the target reliability index is indicated for one or two reference periods (1 year, 50 years or life-time) without providing appropriate links to the design working life. This contribution attempts to clarify the relationship between the target reliability levels, costs of safety measures, failure consequences, reference periods and the design working life. For ultimate limit states of common buildings and bridges (RC2), it is recommended to consider reliability index of 3.8 for a reference period equal to the design working life (50 years for buildings, 100 for bridges).= Рассматриваются условные уровни надежности, рекомендованные в национальных и международных документах. Показано, что эти уровни варьируются в широком диапазоне, в то время как ссылки на соответствующие затраты и последовательность отказов недостаточно изучена. В некоторых документах индекс целевой надежности определяется для одного или двух базовых периодов (1 год, 50 лет или в течение всего жизненного цикла) без предоставления соответствующих ссылок на проекты. В данной работе делается попытка прояснить отношения между уровнями целевой надежности, затратами на обеспечение безопасности, последовательностью отказов, базовыми периодами и сроком эксплуатации. Для предельных уровней состояния общественных зданий и мостов (RC2) рекомендовано использовать целевой индекс 3.8 для периода, равного проектному сроку службы: 50 лет – для зданий,100 лет – для мостов

Toxoplasma gondii, Neospora caninum and Encephalitozoon cuniculi in Animals from Captivity (Zoo and Circus Animals)

Problems with parasitic infections are common in zoological gardens and circuses. In some animals it can lead to several disorders such as systemic disease, reproductive disorders (abortions and neonatal mortality), and even to death if severe illness is untreated. Thus, the aim of this study was to evaluate the prevalence of three common parasites in 74 animals from three zoos, and four circuses in Southern Italy. Antibodies to Toxoplasma gondii, Neospora caninum, and Encephalitozoon cuniculi were detected in 51%, 12%, and 20% of animals, respectively. Co‐infections of T. gondii and N. caninum were reported in seven animals (9%) and co‐infection of T. gondii and E. cuniculi in one animal. T. gondii, N. caninum and E. cuniculi seroprevalence differed in type of diet (P ≤ 0.0001; P ≤ 0.037 and P ≤ 0.004, respectively). T. gondii and E. cuniculi seroprevalence also differed in animal families (P ≤ 0.0001) and according to type of housing (P ≤ 0.003), respectively. Statistical differences were not found in other characteristics (gender, age, country of birth, origin, and contact with cats or dogs). This is the first serological study focusing on protozoan and microsporidian parasites in zoo and circus animals from Southern Italy and the first detection of antibodies to E. cuniculi in camels in Europe

Occupational exposure to saw dust: a case study

ABSTRACT: Occupational exposure to saw dust is associated with the development of oncological diseases, namely nasopharyngeal cancers (about 44% are from nasal cavity and paranasal sinus cancers), in the wood and furniture industries, about 55.000, according to the (Associação das Indústrias de Madeira e Mobiliário de Portugal) AIMMP. It should be noted that since 1995 these dusts have been classified as carcinogenic, by The International Agency for Research on Cancer (IARC). The main objective of this study is to evaluate the exposure to saw dust, quantifying its concentration, comparing with values stipulated by existing legislation and standardization. In order to reach the objectives described above, total dust sampling was performed following the NIOSH0500 methodology, in several jobs, in three different carpentries. From the samplings performed, an average value of saw dust concentration was obtained in each workstation. After analyzing the values obtained in the measurements, performed in the real work context, it was verified there was legal non-compliance in the Garlopa workstation and values of the order of magnitude of the NP 1796 exposure limit values ELV, in the Manual Polishing workstation, in some of the Carpentry Workshops. However, if we consider the Scientific Committee on Occupational Exposure Limit (SCOEL) ELV we can state that only the Trimmer complies with the established ELV. Thus, corrective and/or preventive measures should be implemented by employers and preventive measures should be receptive by workers by implementing/complying to ensure the health and well-being of all, will be proposed.info:eu-repo/semantics/publishedVersio

Adenosine A1-A2A receptor-receptor interaction: contribution to guanosine-mediated effects

Guanosine, a guanine-based purine nucleoside, has been described as a neuromodulator that exerts neuroprotective effects in animal and cellular ischemia models. However, guanosine's exact mechanism of action and molecular targets have not yet been identified. Here, we aimed to elucidate a role of adenosine receptors (ARs) in mediating guanosine effects. We investigated the neuroprotective effects of guanosine in hippocampal slices from A2AR-deficient mice (A2AR-/-) subjected to oxygen/glucose deprivation (OGD). Next, we assessed guanosine binding at ARs taking advantage of a fluorescent-selective A2AR antagonist (MRS7396) which could engage in a bioluminescence resonance energy transfer (BRET) process with NanoLuc-tagged A2AR. Next, we evaluated functional AR activation by determining cAMP and calcium accumulation. Finally, we assessed the impact of A1R and A2AR co-expression in guanosine-mediated impedance responses in living cells. Guanosine prevented the reduction of cellular viability and increased reactive oxygen species generation induced by OGD in hippocampal slices from wild-type, but not from A2AR-/- mice. Notably, while guanosine was not able to modify MRS7396 binding to A2AR-expressing cells, a partial blockade was observed in cells co-expressing A1R and A2AR. The relevance of the A1R and A2AR interaction in guanosine effects was further substantiated by means of functional assays (i.e., cAMP and calcium determinations), since guanosine only blocked A2AR agonist-mediated effects in doubly expressing A1R and A2AR cells. Interestingly, while guanosine did not affect A1R/A2AR heteromer formation, it reduced A2AR agonist-mediated cell impedance responses. Our results indicate that guanosine-induced effects may require both A1R and A2AR co-expression, thus identifying a molecular substrate that may allow fine tuning of guanosine-mediated responses