ABSTRACT Introduction Laboratory fume hoods are mechanical devices used to extract harmful vapours from indoor workplaces in order to prevent human exposure thereto. Laboratory fume hoods are considered an engineering control in the hierarchy of control and are ubiquitous in the modern laboratory. Protection offered by the fume hood depends on whether it is performing according to its original design. This performance needs to be maintained for as long as the fume hood is in use. Gaining a better understanding of this performance and the limitations of the fume hood are essential in ensuring constant operator protection. No performance or measurement standard to which fume hoods need to comply exists in South Africa. The Occupational Health and Safety Act, 1993 (Act no. 85 of 1993) requires engineering controls to be evaluated every 24 months. The Act does not stipulate how such evaluations need to be conducted. The Forensic Science Laboratory (FSL) of the South African Police Service has 49 fume hoods installed in its facility in Silverton, Pretoria. The FSL set a performance standard for its fume hoods at 0.51 m.s-1 ± 20% average across the face of the fume hood. The FSL selected the ANSI/ASHRAE 110 test method to evaluate the performance of its fume hoods against this standard. v Objectives The first objective of the study was to measure face velocities of fume hoods as installed in a forensic science laboratory and calculate the averages, and to determine whether these comply with the set standard. The second objective was to measure face velocities of fume hoods as installed in a forensic science laboratory and calculate the average in order to determine their performance over time. The third study objective was to observe laboratory fume hoods as installed in a forensic science laboratory to see whether fans were operational each month for 11 months (i.e. down time). Methods 10 Observations and 10 tests were carried out on each fume hood. Observations related to whether fume hood fans were functioning or not. Testing was a measure of performance and required the actual measurement of face velocities. A calibrated thermal anemometer was used to take velocity measurements. Measurements taken represent standard velocities. Fume hood faces were divided into imaginary grids not exceeding 30 cm x 30 cm. Velocity measurements were taken at the centre points of these grids. The arithmetic means were calculated for these measurements. The mean of the test means was then vi calculated for every fume hood. This, so that a comparison could be made between the mean and the set standard. Observations indicated that at the onset of the study 14% of fume hoods were not operational. By the end of the study 27% were not operational. A decline of 13% over the study period. At one point during the study 47% of the fume hoods were not functioning. Results 82% of the fume hood population performed outside the standard. 12% underperformed at less than 0.41 m.s-1 while 70% overperformed at velocities exceeding 0.61 m.s-1. ANOVA and regression analyses revealed that performance of the fume hoods over time remained fairly constant (e.g. regression analyses p-value = 0.8538). Discussion and conclusion Fume hood operability and performance results indicate the need for urgent investigation into the correct use of this resource within the FSL. Results are less than satisfactory with the health of laboratory personnel being potentially compromised. Comprehensive procurement, installation, operating and testing procedures need to be compiled, or if available, reviewed and implemented. Further study into the performance of the fume hoods may also be necessary using additional performance indicators.

Inaug.-Diss.--Halle. / Vita. Includes bibliographical references (p. [v]-vi).

No description available.

No description available.

Inaug.-Diss.--Halle. / Vita. Includes bibliographical references (p. [v]-vi).

Holopothrips (Thysanoptera: Phlaeothripidae) é um gênero Neotropical de tripes frequentemente associados a galhas. Dez das 36 espécies atualmente descritas foram coletadas de galhas, em sua maioria indutores destas estruturas, mas pelo menos duas espécies são invasoras de galhas abandonadas de Cecidomyiidae. Duas espécies do gênero foram coletadas causando danos em plantas cultivadas: Holopothrips ananasi em abacaxi, e Holopothrips fulvus em caju, e uma nova espécie descrita neste trabalho é referida como praga em feijoa. Apesar do interesse ecológico do hábito galhador e do potencial interesse econômico, Holopothrips ainda é um grupo pouco estudado, com muitas espécies conhecidas apenas da série tipo, e diversos espécimes sem identificação em coleções ao redor do mundo. Além disso, a diagnose do grupo é limitada, com várias espécies apresentando exceções ou modificações dos caracteres usados para identificar o gênero. Com isso, questionamentos acerca da monofilia de Holopothrips têm sido feitos nos últimos 20 anos. Neste trabalho buscamos preencher algumas destas lacunas no conhecimento de Holopothrips, descrevendo 24 novas espécies, realizando um estudo comparativo da variação morfológica existente no grupo (principalmente interespecífica), elaborando uma chave de identificação ilustrada, e realizando uma análise filogenética do gênero. A partir deste trabalho, o gênero passa a ter 60 espécies reconhecidas, das quais 30 possuem registro de associação com galhas, muitas das quais são ilustradas neste trabalho. Os estudos morfológicos serviram de base para a criação de uma matriz com 140 caracteres e 87 terminais, que foi analisada com base em um critério de parcimônia. Apesar dos valores de suporte obtidos nas análises serem muito baixos para uma revisão da classificação do gênero, foi possível observar algumas tendências nas topologias e otimizações dos caracteres diagnósticos do grupo, que são discutidos. Assim, esperamos prover a base taxonômica e sistemática necessária para a correta identificação do gênero, e para futuros estudos ecológicos e evolutivos desses tripes galhadores. / Holopothrips Hood (Thysanoptera: Phlaeothripidae) is a Neotropical genus of thrips frequently associated to plant galls. Ten out of 36 known species were collected from galls, most of them being the inducers of such structures, but at least two species are invaders of Cecidomyiidae abandoned galls. Two species of the genus were collected damaging crops: Holopothrips ananasi in pineapple, and Holopothrips fulvus in cashew; and a new species described in this work is recorded as a pest in feijoa. Despite the ecological interest in the galling habit and the potential economic importance of the group, the genus Holopothrips is still poorly studied, with several species known only from the type series, and many specimens without identification in collections across the world. Moreover, the diagnosis of the group is limited, with several species having exceptions or modifications of the characters used to identify the genus. With this, questions about the monophyly of Holopothrips have been made in the last twenty years. In this work we attempt to fill in some of these gaps in the knowledge about Holopothrips, describing 24 new species, performing a comparative study of the morphological variation observed in the group (mainly interspecific), proposing an illustrated identification key, and perform a phylogenetic analysis of the genus. With this work, the genus now comprises 60 known species, 30 of them recorded in association with galls, several of which are illustrated here. The morphological studies served as the basis for the creation of a matrix with 140 characters and 87 terminals, which was analyzed using parsimony. Despite the very low support values obtained in the analyses, which do not allow the revision of the systematics of the group, it was possible to observe some tendencies in the topologies and optimization of diagnostic characters of Holopothrips, which are discussed. Thus, we hope to provide the needed taxonomical and systematic basis for the correct identification of the genus, and for future ecological and evolutive studies of these galling thrips.

Holopothrips (Thysanoptera: Phlaeothripidae) é um gênero Neotropical de tripes frequentemente associados a galhas. Dez das 36 espécies atualmente descritas foram coletadas de galhas, em sua maioria indutores destas estruturas, mas pelo menos duas espécies são invasoras de galhas abandonadas de Cecidomyiidae. Duas espécies do gênero foram coletadas causando danos em plantas cultivadas: Holopothrips ananasi em abacaxi, e Holopothrips fulvus em caju, e uma nova espécie descrita neste trabalho é referida como praga em feijoa. Apesar do interesse ecológico do hábito galhador e do potencial interesse econômico, Holopothrips ainda é um grupo pouco estudado, com muitas espécies conhecidas apenas da série tipo, e diversos espécimes sem identificação em coleções ao redor do mundo. Além disso, a diagnose do grupo é limitada, com várias espécies apresentando exceções ou modificações dos caracteres usados para identificar o gênero. Com isso, questionamentos acerca da monofilia de Holopothrips têm sido feitos nos últimos 20 anos. Neste trabalho buscamos preencher algumas destas lacunas no conhecimento de Holopothrips, descrevendo 24 novas espécies, realizando um estudo comparativo da variação morfológica existente no grupo (principalmente interespecífica), elaborando uma chave de identificação ilustrada, e realizando uma análise filogenética do gênero. A partir deste trabalho, o gênero passa a ter 60 espécies reconhecidas, das quais 30 possuem registro de associação com galhas, muitas das quais são ilustradas neste trabalho. Os estudos morfológicos serviram de base para a criação de uma matriz com 140 caracteres e 87 terminais, que foi analisada com base em um critério de parcimônia. Apesar dos valores de suporte obtidos nas análises serem muito baixos para uma revisão da classificação do gênero, foi possível observar algumas tendências nas topologias e otimizações dos caracteres diagnósticos do grupo, que são discutidos. Assim, esperamos prover a base taxonômica e sistemática necessária para a correta identificação do gênero, e para futuros estudos ecológicos e evolutivos desses tripes galhadores. / Holopothrips Hood (Thysanoptera: Phlaeothripidae) is a Neotropical genus of thrips frequently associated to plant galls. Ten out of 36 known species were collected from galls, most of them being the inducers of such structures, but at least two species are invaders of Cecidomyiidae abandoned galls. Two species of the genus were collected damaging crops: Holopothrips ananasi in pineapple, and Holopothrips fulvus in cashew; and a new species described in this work is recorded as a pest in feijoa. Despite the ecological interest in the galling habit and the potential economic importance of the group, the genus Holopothrips is still poorly studied, with several species known only from the type series, and many specimens without identification in collections across the world. Moreover, the diagnosis of the group is limited, with several species having exceptions or modifications of the characters used to identify the genus. With this, questions about the monophyly of Holopothrips have been made in the last twenty years. In this work we attempt to fill in some of these gaps in the knowledge about Holopothrips, describing 24 new species, performing a comparative study of the morphological variation observed in the group (mainly interspecific), proposing an illustrated identification key, and perform a phylogenetic analysis of the genus. With this work, the genus now comprises 60 known species, 30 of them recorded in association with galls, several of which are illustrated here. The morphological studies served as the basis for the creation of a matrix with 140 characters and 87 terminals, which was analyzed using parsimony. Despite the very low support values obtained in the analyses, which do not allow the revision of the systematics of the group, it was possible to observe some tendencies in the topologies and optimization of diagnostic characters of Holopothrips, which are discussed. Thus, we hope to provide the needed taxonomical and systematic basis for the correct identification of the genus, and for future ecological and evolutive studies of these galling thrips.

Holopothrips (Thysanoptera: Phlaeothripidae) é um gênero Neotropical de tripes frequentemente associados a galhas. Dez das 36 espécies atualmente descritas foram coletadas de galhas, em sua maioria indutores destas estruturas, mas pelo menos duas espécies são invasoras de galhas abandonadas de Cecidomyiidae. Duas espécies do gênero foram coletadas causando danos em plantas cultivadas: Holopothrips ananasi em abacaxi, e Holopothrips fulvus em caju, e uma nova espécie descrita neste trabalho é referida como praga em feijoa. Apesar do interesse ecológico do hábito galhador e do potencial interesse econômico, Holopothrips ainda é um grupo pouco estudado, com muitas espécies conhecidas apenas da série tipo, e diversos espécimes sem identificação em coleções ao redor do mundo. Além disso, a diagnose do grupo é limitada, com várias espécies apresentando exceções ou modificações dos caracteres usados para identificar o gênero. Com isso, questionamentos acerca da monofilia de Holopothrips têm sido feitos nos últimos 20 anos. Neste trabalho buscamos preencher algumas destas lacunas no conhecimento de Holopothrips, descrevendo 24 novas espécies, realizando um estudo comparativo da variação morfológica existente no grupo (principalmente interespecífica), elaborando uma chave de identificação ilustrada, e realizando uma análise filogenética do gênero. A partir deste trabalho, o gênero passa a ter 60 espécies reconhecidas, das quais 30 possuem registro de associação com galhas, muitas das quais são ilustradas neste trabalho. Os estudos morfológicos serviram de base para a criação de uma matriz com 140 caracteres e 87 terminais, que foi analisada com base em um critério de parcimônia. Apesar dos valores de suporte obtidos nas análises serem muito baixos para uma revisão da classificação do gênero, foi possível observar algumas tendências nas topologias e otimizações dos caracteres diagnósticos do grupo, que são discutidos. Assim, esperamos prover a base taxonômica e sistemática necessária para a correta identificação do gênero, e para futuros estudos ecológicos e evolutivos desses tripes galhadores. / Holopothrips Hood (Thysanoptera: Phlaeothripidae) is a Neotropical genus of thrips frequently associated to plant galls. Ten out of 36 known species were collected from galls, most of them being the inducers of such structures, but at least two species are invaders of Cecidomyiidae abandoned galls. Two species of the genus were collected damaging crops: Holopothrips ananasi in pineapple, and Holopothrips fulvus in cashew; and a new species described in this work is recorded as a pest in feijoa. Despite the ecological interest in the galling habit and the potential economic importance of the group, the genus Holopothrips is still poorly studied, with several species known only from the type series, and many specimens without identification in collections across the world. Moreover, the diagnosis of the group is limited, with several species having exceptions or modifications of the characters used to identify the genus. With this, questions about the monophyly of Holopothrips have been made in the last twenty years. In this work we attempt to fill in some of these gaps in the knowledge about Holopothrips, describing 24 new species, performing a comparative study of the morphological variation observed in the group (mainly interspecific), proposing an illustrated identification key, and perform a phylogenetic analysis of the genus. With this work, the genus now comprises 60 known species, 30 of them recorded in association with galls, several of which are illustrated here. The morphological studies served as the basis for the creation of a matrix with 140 characters and 87 terminals, which was analyzed using parsimony. Despite the very low support values obtained in the analyses, which do not allow the revision of the systematics of the group, it was possible to observe some tendencies in the topologies and optimization of diagnostic characters of Holopothrips, which are discussed. Thus, we hope to provide the needed taxonomical and systematic basis for the correct identification of the genus, and for future ecological and evolutive studies of these galling thrips.

No description available.

In November, 2006, a storm generated a minimum of 34 cm of precipitation in six days, triggering debris flows in many of the drainages on all sides of Mount Hood, Oregon. Of the eleven drainages surveyed, seven experienced debris flows; these include the White River, Salmon River, Clark Creek, Newton Creek, Eliot Creek, Ladd Creek and Sandy River basins. Flows in the White River, Eliot Creek, and Newton Creek, caused major damage to bridges and roadways. Initiation elevations averaged around 1,860 meters. Initiation zone material was predominantly sand (45-82%) with gravel (15-49%) and had few fines (3-5%). Four debris flows were triggered by landslides caused by undercutting of the river banks. Three developed through coalescence of multiple small debris flows within major channels and were termed "headless debris flows". Physical and morphological characterization of source areas was used to assess factors controlling debris flow initiation. Although findings indicate that all major drainages on Mount Hood are capable of producing debris flows, drainages with direct connection to a glacier, low percentages of vegetation, and moderate gradients in the upper basin were the most susceptible. Among basins not having debris flows, neither the Zigzag River nor Polallie Creek have a direct connection to a glacier, And the Muddy Fork and the Coe both have high percentages of vegetated slopes. The material in the upper basin of the Muddy Fork is predominately rock making initiation there weathering-limited. Additionally, the Muddy Fork and the Zigzag have two of the steepest gradients on the mountain. This pattern suggests that material there is regularly transported downstream through normal fluvial processes rather than building up to be catastrophically removed through debris flow processes.