Death of firefighters due to structural collapse has been on the rise for the past few years, and has not gone unnoticed by the research and firefighting branches of the industry. However, the modes for improving this situation by both are very different. While firefighters depend on experience for detection, research organizations have invested in developing new technology to detect signs of structural collapse. Thus far neither effort has led to any improvement in the current circumstances. In order to bridge this gap, members of the fire-safety community need to more thoroughly understand the reasons for structural collapse due to fire. Through research and analysis, a case study manual analyzing structural steel failures due to fire was developed. This manual contains analysis of the actual mode of failure for the cases chosen, as well as analysis of alternative situations for each case that may have led to different outcomes. The goal of this manual is to aid in the teaching and practice of structural steel collapse due to fire as a supplement to current knowledge.

Sérios problemas ambientais têm origem em processos de combustão incompletos. Entre os produtos indesejados está a fuligem, considerada como um dos principais fatores da mudança climática observada nos último anos. Desta forma, ferramentas para diagnóstico da emissão de material particulado se fazem necessárias. Com o advento do laser, o desenvolvimento de técnicas óticas não intrusivas teve início. Dentre elas, destaca-se a técnica denominada incandescência induzida por laser (laser induced incandescence – LII), a qual pode gerar resultados resolvidos no espaço para a fração volumétrica de fuligem. Neste contexto, este trabalho apresenta um estudo experimental sobre a produção de fuligem em duas situações: na primeira, foram estudadas chamas laminares pré-misturadas de etileno e ar aplicando-se a técnica LII. Os resultados foram calibrados a partir da fração volumétrica de fuligem média empregando a técnica de extinção de luz, obtendo-se, então, resultados quantitativos espacialmente resolvidos da fração volumétrica de fuligem. A utilização de diferentes gases no escoamento anular também foi avaliada. A segunda situação abordada envolve o estudo de chamas laminares não pré-misturadas utilizando o gás natural como combustível. O impacto da diluição de inertes em diferentes proporções sobre a fração volumétrica de fuligem em diversas alturas da chama foi estudado por meio da técnica LII. Os resultados obtidos foram comparados à outros resultados presentes na literatura e servirão como validação de futuros modelos de formação de fuligem. / Serious environmental problems are assigned to incomplete combustion processes. Among the unwanted products, soot can be related as an important factor of climate changes observed in the last years. Thus, particulate material emissions diagnostic tools are necessary. Due the laser advent, the development of non-intrusive optical techniques was possible. One of the most importante technique is the laser induced incandescence, LII, which can generate spatially and temporally resolved results of soot volume fraction. In this context, an experimental study regarding the soot production was developed in two different situations: in the first one, premixed laminar flames of ethylene and air were investigated by applying the LII technique. The results were calibrated through the average of soot volume fraction results obtained by the light extinction technique. Therefore, it was possible to obtain quantitative results of spatially resolved soot volume fraction. Different gases employment at the annular flow were also evaluated. The second situation studied involves the analysis of natural gas laminar non-premixed flames. The impact of different inert gas dilution ratio on the soot volume fraction at different heights of the flame was evaluated by the LII technique. The results were compared to other authors and will serve as validation for future soot formation models.

O atual processo de reestruturação produtiva trouxe profundas transformações na gestão e na organização do trabalho no contexto das universidades públicas no Brasil, repercutindo na saúde de seus servidores. A extinção de cargos no âmbito do serviço público federal, preconizada no Plano Diretor da Reforma do Estado nos anos 1990 e implementada pela Lei nº 9.632 de 1998, atinge o conjunto do funcionalismo, incidindo nas universidades públicas federais. Assim, esta pesquisa objetiva dar visibilidade aos efeitos das transformações ocorridas nas universidades públicas federais na saúde e no trabalho dos servidores ocupantes de cargos em processo de extinção. Trata-se de um estudo qualitativo, desenvolvido na Universidade Federal do Rio Grande do Sul (UFRGS), o qual contou com a realização de entrevistas semiestruturadas com nove servidores ativos ocupantes de cargos em processo de extinção, um representante do setor de gestão de pessoas e um representante sindical. As entrevistas, depois de transcritas, foram submetidas à análise de conteúdo temática e divididas considerando-se as seguintes categorias: mercado de trabalho; condições de trabalho; saberes do trabalho; relações do e no trabalho; relações entre trabalho e outras dimensões da vida; cargo e atividades desempenhadas. Os servidores descrevem as dificuldades de inserção no mercado de trabalho como a principal justificativa para ingresso e permanência na universidade. A escolaridade acima da exigida pelo cargo e o amplo conhecimento institucional adquirido ao longo dos anos de trabalho, aliados à falta de servidores em algumas áreas, contribuem para que suas atividades se modifiquem ao longo dos anos. Tal contexto permite a estes servidores suprir lacunas institucionais, tornando o desvio de função uma das principais características desses cargos. Práticas de gestão com caráter fortemente culpabilizante e individualizante levam ao ocultamento dos processos institucionais que constituem a realidade de trabalho desses servidores. O enfrentamento das dificuldades se dá predominantemente por meio de estratégias individuais, as quais, conjuntamente com as frágeis estratégias coletivas sustentadas nas relações de troca e ajuda mútua, têm efeitos meramente paliativos, sendo incapazes de modificar a condição em que os servidores se encontram. Conclui-se que o trabalho destes servidores é composto por um conjunto de elementos heterogêneos e contraditórios, no seio do qual lhes restam poucas e limitadas alternativas, sendo as estratégias individuais por eles empregadas incapazes de solucionar as dificuldades enfrentadas. O sofrimento social emerge como principal efeito das mudanças da universidade na saúde dos servidores ocupantes de cargos em extinção. / The current productive reorganization process has brought significant changes in management and organization of work in the context of public universities in Brazil, which has influenced the health of their public servants. The extinction of positions in Brazil’s national public service, as advocated in the Directive Plan of the State Reform in the 1990s and implemented by Law n. 9.632, from 1998, affects the entire public workers category, including the ones who work in national public universities. Therefore, this research aims to give visibility to the effects of changes occurred in the national public universities considering health and work of public servants who have a job position which is becoming extinct. The study was developed at Federal University of Rio Grande do Sul (UFRGS) and included semi-structured interviews with nine active public servants who have a job position which is becoming extinct, a representative of the people management department and a union labor representative. The interviews, after transcribed, underwent thematic content analysis and were divided considering the following categories: labor market; working conditions; knowledge about the job; relationships of and in work; relationships between work and other aspects of life; job and activities performed. Public servants describe the difficulties to enter the labor market as the main reason to start and stay working in the university. Their education, higher than required by the position, and the broad institutional knowledge acquired over the years of work, along with the lack of public servants in some areas, contribute for a change on their activities over the years. This context allows these public servants to fill institutional gaps, which makes the change in the work performed be one of the main characteristics of these positions. Strong guilt-inducing and individualizing management practices lead to hiding institutional processes which are a working reality to these servants. The difficulties are faced predominantly through individual strategies, which, along with the fragile collective strategies sustained in the exchanging relationships and mutual support, have only palliative effects, being unable to change the condition in which the servants are. These servers’ jobs are composed by a set of heterogeneous and contradictory elements and, thus, there are few and limited alternatives left, and the individual strategies used by them are unable to solve the difficulties faced. Social suffering emerges as the main effect of the changes of the university on the health of public servants who have a job position which is becoming extinct.

Through common descent, closely-related taxa share many life history traits, some of which can influence extinction-proneness. Thus, examining historical and contemporary genetic patterns is valuable in accounting for evolutionary and ecological processes that may be critical to the successful conservation of threatened species. Unsustainable harvesting of monk seals (tribe Monachini) until the late nineteenth century caused the recent extinction of Caribbean monk seals (Neomonachus tropicalis) and critically low population sizes for Hawaiian and Mediterranean monk seals (Neomonachus schauinslandi and Monachus monachus, respectively). Having lost one branch of its evolutionary lineage, and with a second branch threatened by extinction, the genus Neomonachus can serve as a valuable case for examining evolutionary and ecological linkages that are sensitive to non-random anthropogenic selection pressure. An important foundation for such pursuits is the understanding of evolutionary sequences of speciation and diversification that gave rise to common traits shared by extinct and vulnerable species. Further consideration of the phylogenetic non-randomness of species vulnerability requires examination of genetic variation at the population level to infer the presence of fundamental processes (e.g., migration and reproduction) that directly influence population viability. This dissertation includes three individual studies that make use of molecular systematic and population genetic techniques to address these topics. First, a complete mitochondrial genome sequence of the extinct Caribbean monk seal (N. tropicalis) was assembled and used to resolve long-standing phylogenetic questions regarding the sequence of divergence among monk seal species and sister taxa. Second, novel microsatellite marker assays were developed and used to characterize the extent of population-level variation across 24 polymorphic microsatellite loci of 1192 endangered Hawaiian monk seals (N. schauinslandi) that were sampled during a longitudinal study spanning three decades. Third, resulting genotypes from a subset of individuals (N= 785) were integrated with previously reported genotypes consisting of 18 other loci for the largest ever population-level assessment of N. schauinslandi genetic diversity and population differentiation throughout the Hawaiian archipelago. The new microsatellite data will be of particular value for future individual-level assessment of parentage and relatedness in N. schauinslandi, which will help managers better infer the reproductive mechanisms that factor into population persistence and recovery. Results of this study expand understanding of the evolutionary and conservation genetic status of monk seals, as well as molecular genetic capacity, for future research regarding a unique and highly imperiled New World pinniped lineage.

Learning allows animals to adapt their behaviour to changes in the environment. In humans and other mammals, memories are stored in the hippocampus and cerebellum, whereas in insects, they are stored inside the mushroom bodies (MB). Here, MB-intrinsic Kenyon cells (KCs) form plastic synapses to MB output neurons (MBONs) that are modulated by the reinforcing action of dopaminergic neurons (DANs). Despite decades of research on the MB, the main neurotransmitter underlying the plastic KC → MBON synapse has remained a mystery. Here, I show that this synapse is cholinergic in the fruit fly Drosophila melanogaster. MBONs show fast excitatory responses to direct acetylcholine (ACh) application. KCs synthesise ACh-related proteins ChAT and VAChT. MBONs express and require nicotinic ACh receptors (nAChRs) to become fully activated by odour presentation. Lastly, artificial activation of KCs leads to MBON calcium responses that are blocked by nicotinic antagonists and genetic reduction of VAChT in KCs. Short neuropeptide F (sNPF) may play a role as a modulatory co-transmitter that can either excite or inhibit specific MBONs and DANs. The retrieval of memories is state-dependent and known to potentially change the original memory. Fruit flies need to be hungry to express appetitive memories. Hunger state depends on insulin signalling that activates the GABAergic MBON MVP2, while appetitive memory retrieval depends on decreased activity in M4/6 MBONs. Here, I show that optogenetic MVP2 activation acutely inhibits M4/6 odour responses, rendering MVP2 an inhibitory MBON interneuron. I also show that other MBONs are functionally connected to DANs, thus linking memory reinforcement and retrieval pathways in a way that enables the updating of the original memory. These findings show that associative memories in Drosophila are initially formed at cholinergic-MBON synapses, and can be retrieved and modified through an intricate KC-MBON-DAN network.

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004. / Includes bibliographical references (leaves 73-76). / The recent trend of using fine water mist systems to replace the legacy HALON- 1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 pm droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed. Preliminary design of a full-scale system was examined. / (cont.) Given the recent trend toward tumblehome hull forms in future Naval Combatant designs, there exists strong applicability of this system in the "dead" spaces created by the shaping of the tumblehome hull. Further work is needed in numerical modeling and laboratory testing of specific phases of the mitigation. The end goal is a feasible design of a blast mitigation system to be used in the outermost spaces of Naval Combatants to protect interior vital system spaces. / by Julie A. Kitchenka. / S.M. / Nav.E.

Practical gas turbine engine combustors create extremely non-uniform flowfields, which are highly stratified making it imperative that similar environments are well understood. Laser diagnostics were utilized in a variety of stratified environments, which led to temperature or chemical composition gradients, to better understand autoignition, extinction, and flame stability behavior. This work ranged from laminar and steady flames to turbulent flame studies in which time resolved measurements were used. Edge flames, formed in the presence of species stratification, were studied by first developing a simple measurement technique which is capable of estimating an important quantity for edge flames, the advective heat flux, using only velocity measurements. Both hydroxyl planar laser induced fluorescence (OH PLIF) and particle image velocimetry (PIV) were used along with numerical simulations in the development of this technique. Interacting triple flames were also created in a laboratory scale burner producing a laminar and steady flowfield with symmetric equivalence ratio gradients. Studies were conducted in order to characterize and model the propagation speed as a function of the flame base curvature and separation distance between the neighboring flames. OH PLIF, PIV and Rayleigh scattering measurements were used in order to characterize the propagation speed. A model was developed which is capable of accurately representing the propagation speed for three different fuels. Negative edge flames were first studied by developing a one-dimensional model capable of reproducing the energy equation along the stoichiometric line, which was dependent on different boundary conditions. Unsteady and laminar negative edge flames were also simulated with periodic boundary conditions in order to assess the difference between the steady and unsteady cases. The diffusive heat loss was unbalanced with the chemical heat release and advective heat flux energy gain terms which led to the flame proceeding and receding. The temporal derivative balanced the energy equation, but also aided in the understanding of negative edge flame speeds. Turbulent negative edge flame velocities were measured for extinguishing flames in a separate experiment as a function of the bulk advective heat flux through the edge and turbulence level. A burner was designed and built for this study which created statistically stationary negative edge flames. The edge velocity was dependent on both the bulk advective heat flux and turbulence levels. The negative edge flame velocities were obtained with high speed stereo-view chemiluminescence and two dimensional PIV measurements. Autoignition stabilization was studied in the presence of both temperature and species stratification, using a simple laminar flowfield. OH and CH2O PLIF measurements showed autoignition characteristics ahead of the flame base. Numerical chemical and flow simulations also revealed lower temperature chemistry characteristics ahead of the flame base leading to the conclusion of lower temperature chemistry dominating the stabilization behavior. An energy budget analysis was conducted which described the stabilization behavior.

Thesis (M.Dev.) --University of Limpopo, 2012 / The main aim or purpose of this study was to look at the ways and the strategies of minimizing\ mitigating the over-harvesting of indigenous medicinal plants in order to use them sustainably. The task of identifying and assessing challenges facing local communities in utilizing and sustaining indigenous medicinal plants in Thengwe village and their implications on environmental conservation and management of natural resources was done during the pilot survey. The environmental field survey was conducted after gaining permission to enter into the identified study areas including the Mutavhatsindi Nature Reserve. The result revealed that most of the indigenous medicinal plants are used for healing, religious, economical and for protection purposes. Most of the indigenous medicinal plants in the study area are depleted and many of them are facing extinction. The study was qualitative in design. Semi-structured interviews and a questionnaire were used. The questionnaire had both open-ended and closed questions. The study area was Thengwe Village in the Mutale Municipality. The existence of medicinal plants is threatened by people `s perceptions and attitudes towards them. For some indigenous medicinal plants, depletion is at a high rate due to over-harvesting and because the plants when traded by herbalists they have a premium price attached to them. Interestingly, perhaps surprisingly, the majority of young people hold negative attitudes towards the indigenous medicinal plants due to poor knowledge of the value of indigenous medicinal plants, in contrast to the elders who appreciate their role and consider them as part of their culture, economy and religion. One of the findings is that medicinal plants were found to be important to the community members as the source of income and creation of jobs for the medicinal collectors who sell the species to traditional healers. For the reason of preserving indigenous medicinal plants and others as the environmental resources, this study recommends that there should be strong intergovernmental relationships between the National, Provincial and Local governments in order to prevent over-harvesting of the medicinal plants. The indigenous medicinal plants are equally important to biodiversity students and researchers who want to study and research indigenous medicinal plants which play an important role in the improvement of the livelihoods of community members. Furthermore, education campaigns within the communities and school learners are recommended to encourage the prevention, sustainability and utilization of the indigenous medicinal plants. Additionally, the legal authorities should be empowered to prosecute all people who may be found illegally in possession of indigenous medicinal plants, as well as endangered and protected species. Heavy fines and charges should be imposed on such culprits. Of importance is the fact that the results and recommendations of this study may facilitate the teaching of environmental education and management of natural resources as well as boost the local economy of the Vhembe district Municipality by showing that medicinal plants in the area can be seen as a viable tourist attraction.

Eleven experiments examined two late-developing learning and memory systems in rats: fear-potentiated startle (FPS) and the contextual regulation of latent inhibition and extinction. The first study was based on three previous developmental findings on FPS: (1) FPS to an odour CS emerges at postnatal day (PN) 23; Rats conditioned at PN16 to an odour CS express freezing but not FPS when tested at PN23, and (3) FPS to an odour CS trained at PN16 is activated if rats are also trained to a difference odour at PN23 (Yap, Stapinski, & Richardson, 2005). Yap et al. (2005) hypothesised that the activation effect only occurs if rats are given training to the second odour at an age when FPS has emerged. Study 1 assessed this hypothesis and trained the second odour CS at either PN23 or PN20. Contrary to expectations, the results of this study showed the activation effect for both groups of rats. Surprisingly, the results also revealed a significant FPS effect to the odour CS trained at PN20. Subsequent experiments examined this unexpected result, and found that learning to odour 1 at PN16 facilitated the age of onset for FPS at PN20. The results of Study 1 are discussed in relation to past findings on enrichment, cumulative learning, and neurobiological models of conditioned fear. The second section of this thesis (Studies 2 and 3) examined the context-specificity of two memory interference paradigms, latent inhibition and extinction, in developing rats. The studies found that both phenomena were context-specific at PN23-25 but not at PN16-18. Moreover, the results suggest that the context-specificity of both latent inhibition depended on the age of the rat during the second phase of training, but not their age during the first phase of training or their age at test. The implications of these findings for theoretical and neural models of learning, as well as the occurrence of latent inhibition and extinction during development are discussed.

<p>Many of the earth’s ecosystems are experiencing large species losses due to human impacts such as habitat destruction and fragmentation, climate change, species invasions, pollution, and overfishing. Due to the complex interactions between species in food webs the extinction of one species could lead to a cascade of further extinctions and hence cause dramatic changes in species composition and ecosystem processes. The complexity of ecological systems makes it difficult to study them empirically. The systems often consist of large species numbers with lots of interactions between species. Investigating ecological communities within a theoretical approach, using mathematical models and computer simulations, is an alternative or a complement to experimental studies. This thesis is a collection of theoretical studies. We use model food webs in order to explore how biodiversity (species number) affects the response of communities to species loss (Paper I-III) and to environmental variability (Paper IV).</p><p>In paper I and II we investigate the risk of secondary extinctions following deletion of one species. It is shown that resistance against additional species extinctions increases with redundancy (number of species per functional group) (Paper I) in the absence of competition between basal species but decreases with redundancy in the presence of competition between basal species (Paper II). It is further shown that food webs with low redundancy run the risk of losing a greater proportion of species following a species deletion in a deterministic environment but when demographic stochasticity is included the benefits of redundancy are largely lost (Paper II). This finding implies that in the construction of nature reserves the advantages of redundancy for conservation of communities may be lost if the reserves are small in size. Additionally, food webs show higher risks of further extinctions after the loss of basal species and herbivores than after the loss of top predators (Paper I and II).</p><p>Secondary extinctions caused by a primary extinction and mediated through direct and indirect effects, are likely to occur with a time delay since the manifestation of indirect effects can take long time to appear. In paper III we show that the loss of a top predator leads to a significantly earlier onset of secondary extinctions in model communities than does the loss of a species from other trophic levels. If local secondary extinctions occur early they are less likely to be balanced by immigration of species from local communities nearby implying that secondary extinctions caused by the loss of top predators are less likely to be balanced by dispersal than secondary extinctions caused by the loss of other species. As top predators are vulnerable to human-induced disturbances on ecosystems in the first place, our results suggest that conservation of top predators should be a priority. Moreover, in most cases time to secondary extinction is shown to increase with species richness indicating the decay of ecological communities to be slower in species-rich than in species-poor communities.</p><p>Apart from the human-induced disturbances that often force species towards extinction the environment is also, to a smaller or larger extent, varying over time in a natural way. Such environmental stochasticity influences the dynamics of populations. In paper IV we compare the responses of food webs of different sizes to environmental stochasticity. Species-rich webs are found to be more sensitive to environmental stochasticity. Particularly, species-rich webs lose a greater proportion of species than species-poor webs and they also begin losing species faster than species-poor webs. However, once one species is lost time to final extinction is longer in species-rich webs than in species-poor webs. We also find that the results differ depending on whether species respond similarly to environmental fluctuations or whether they are totally uncorrelated in their response. For a given species richness, communities with uncorrelated species responses run a considerable higher risk of losing a fixed proportion of species compared with communities with correlated species responses.</p>