Study of the problem of the Los Angeles sewage disposal

No abstract.

Special Sewage Problem : Report on the Sewage Problem of the City of Los Angeles with Conclusions and Recommendations

Not available.

A multiple scattering problem

The present work deals with the problem of the interaction of the electromagnetic radiation with a statistical distribution of nonmagnetic dielectric particles immersed in an infinite homogeneous isotropic, non-magnetic medium. The wavelength of the incident radiation can be less, equal or greater than the linear dimension of a particle. The distance between any two particles is several wavelengths. A single particle in the absence of the others is assumed to scatter like a Rayleigh-Gans particle, i.e. interaction between the volume elements (self-interaction) is neglected. The interaction of the particles is taken into account (multiple scattering) and conditions are set up for the case of a lossless medium which guarantee that the multiple scattering contribution is more important than the self-interaction one. These conditions relate the wavelength λ and the linear dimensions of a particle a and of the region occupied by the particles D. It is found that for constant λ/a, D is proportional to λ and that |Δχ|, where Δχ is the difference in the dielectric susceptibilities between particle and medium, has to lie within a certain range.

The total scattering field is obtained as a series the several terms of which represent the corresponding multiple scattering orders. The first term is a single scattering term. The ensemble average of the total scattering intensity is then obtained as a series which does not involve terms due to products between terms of different orders. Thus the waves corresponding to different orders are independent and their Stokes parameters add.

The second and third order intensity terms are explicitly computed. The method used suggests a general approach for computing any order. It is found that in general the first order scattering intensity pattern (or phase function) peaks in the forward direction Θ = 0. The second order tends to smooth out the pattern giving a maximum in the Θ = π/2 direction and minima in the Θ = 0 , Θ = π directions. This ceases to be true if ka (where k = 2π/λ) becomes large (> 20). For large ka the forward direction is further enhanced. Similar features are expected from the higher orders even though the critical value of ka may increase with the order.

The first order polarization of the scattered wave is determined. The ensemble average of the Stokes parameters of the scattered wave is explicitly computed for the second order. A similar method can be applied for any order. It is found that the polarization of the scattered wave depends on the polarization of the incident wave. If the latter is elliptically polarized then the first order scattered wave is elliptically polarized, but in the Θ = π/2 direction is linearly polarized. If the incident wave is circularly polarized the first order scattered wave is elliptically polarized except for the directions Θ = π/2 (linearly polarized) and Θ = 0, π (circularly polarized). The handedness of the Θ = 0 wave is the same as that of the incident whereas the handedness of the Θ = π wave is opposite. If the incident wave is linearly polarized the first order scattered wave is also linearly polarized. The second order makes the total scattered wave to be elliptically polarized for any Θ no matter what the incident wave is. However, the handedness of the total scattered wave is not altered by the second order. Higher orders have similar effects as the second order.

If the medium is lossy the general approach employed for the lossless case is still valid. Only the algebra increases in complexity. It is found that the results of the lossless case are insensitive in the first order of k_imD where k_im = imaginary part of the wave vector k and D a linear characteristic dimension of the region occupied by the particles. Thus moderately extended regions and small losses make (k_imD)² ≪ 1 and the lossy character of the medium does not alter the results of the lossless case. In general the presence of the losses tends to reduce the forward scattering.

Some theorems in classical elastodynamic

This investigation is concerned with various fundamental aspects of the linearized dynamical theory for mechanically homogeneous and isotropic elastic solids. First, the uniqueness and reciprocal theorems of dynamic elasticity are extended to unbounded domains with the aid of a generalized energy identity and a lemma on the prolonged quiescence of the far field, which are established for this purpose. Next, the basic singular solutions of elastodynamics are studied and used to generate systematically Love's integral identity for the displacement field, as well as an associated identity for the field of stress. These results, in conjunction with suitably defined Green's functions, are applied to the construction of integral representations for the solution of the first and second boundary-initial value problem. Finally, a uniqueness theorem for dynamic concentrated-load problems is obtained.

On the uniqueness of singular solutions to boundary-initial value problems in linear elastodynamics

This investigation deals with certain generalizations of the classical uniqueness theorem for the second boundary-initial value problem in the linearized dynamical theory of not necessarily homogeneous nor isotropic elastic solids. First, the regularity assumptions underlying the foregoing theorem are relaxed by admitting stress fields with suitably restricted finite jump discontinuities. Such singularities are familiar from known solutions to dynamical elasticity problems involving discontinuous surface tractions or non-matching boundary and initial conditions. The proof of the appropriate uniqueness theorem given here rests on a generalization of the usual energy identity to the class of singular elastodynamic fields under consideration.

Following this extension of the conventional uniqueness theorem, we turn to a further relaxation of the customary smoothness hypotheses and allow the displacement field to be differentiable merely in a generalized sense, thereby admitting stress fields with square-integrable unbounded local singularities, such as those encountered in the presence of focusing of elastic waves. A statement of the traction problem applicable in these pathological circumstances necessitates the introduction of "weak solutions'' to the field equations that are accompanied by correspondingly weakened boundary and initial conditions. A uniqueness theorem pertaining to this weak formulation is then proved through an adaptation of an argument used by O. Ladyzhenskaya in connection with the first boundary-initial value problem for a second-order hyperbolic equation in a single dependent variable. Moreover, the second uniqueness theorem thus obtained contains, as a special case, a slight modification of the previously established uniqueness theorem covering solutions that exhibit only finite stress-discontinuities.

Computer system support for data analysis

This thesis is an investigation into the nature of data analysis and computer software systems which support this activity.

The first chapter develops the notion of data analysis as an experimental science which has two major components: data-gathering and theory-building. The basic role of language in determining the meaningfulness of theory is stressed, and the informativeness of a language and data base pair is studied. The static and dynamic aspects of data analysis are then considered from this conceptual vantage point. The second chapter surveys the available types of computer systems which may be useful for data analysis. Particular attention is paid to the questions raised in the first chapter about the language restrictions imposed by the computer system and its dynamic properties.

The third chapter discusses the REL data analysis system, which was designed to satisfy the needs of the data analyzer in an operational relational data system. The major limitation on the use of such systems is the amount of access to data stored on a relatively slow secondary memory. This problem of the paging of data is investigated and two classes of data structure representations are found, each of which has desirable paging characteristics for certain types of queries. One representation is used by most of the generalized data base management systems in existence today, but the other is clearly preferred in the data analysis environment, as conceptualized in Chapter I.

This data representation has strong implications for a fundamental process of data analysis -- the quantification of variables. Since quantification is one of the few means of summarizing and abstracting, data analysis systems are under strong pressure to facilitate the process. Two implementations of quantification are studied: one analagous to the form of the lower predicate calculus and another more closely attuned to the data representation. A comparison of these indicates that the use of the "label class" method results in orders of magnitude improvement over the lower predicate calculus technique.

The microbiological quality of water: the nature of the problem

Improvements in methods for the detection and enumeration of microbes in water, particularly the application of techniques of molecular biology, have highlighted shortcomings in the ”standard methods” for assessing water quality. Higher expectations from the consumer and increased publicity associated with pollution incidents can lead to an uncoupling of the cycle which links methodological development with standard-setting and legislation. The new methodology has also highlighted problems within the water cycle, related to the introduction, growth and metabolism of microbes. A greater understanding of the true diversity of the microbial community and the ability to transmit genetic information within aquatic systems ensures that the subject of this symposium and volume provides an ideal forum to discuss the problems encountered by both researcher and practitioner.

Eventos de vida produtores de estresse e acidentes de trabalho: Estudo Pró-Saúde, Rio de Janeiro - Brasil

A proposta desta tese consiste em um recorte de uma abordagem mais ampla da determinação dos acidentes de trabalho, e tem como objetivo geral investigar o perfil de acidentes de trabalho que acometem funcionários técnico-administrativos do quadro efetivo de uma universidade do Rio de Janeiro. Para o alcance do objetivo, esta tese está estruturada em dois artigos, e como tal pretende explorar o perfil sócio-demográfico e ocupacional de funcionários públicos na ocorrência de acidentes de trabalho (Artigo 1); e investigar a associação entre os eventos de vida produtores de estresse (EVPE) e a ocorrência de acidentes de trabalho (Artigo 2). Dados seccionais da fase 2 de um estudo de natureza prospectiva (Estudo Pró-Saúde) foram coletados entre 3572 funcionários. A história de acidentes de trabalho foi captada por meio de perguntas dicotômicas (sim vs. não) para cada um dos seguintes tipos de acidentes: perfuração com agulha; perfuração com outro objeto; corte; queimadura; choque elétrico; contusão ou distensão muscular; fratura, entorse ou luxação; e envenenamento ou intoxicação. O período de referência para aferição tanto dos EVPE quanto da ocorrência de acidente de trabalho correspondeu aos 12 meses anteriores a aplicação de questionário autopreenchível. No artigo 1 utilizou-se a técnica de análise de correspondência múltipla para delimitar agrupamentos de funcionários quanto ao perfil sócio-demográfico e ocupacional associado à ocorrência de acidente de trabalho, de acordo com as seguintes Característica : sexo, idade, escolaridade, renda per capita, ocupação, setor e local de trabalho. No artigo 2, a associação entre EVPE e acidentes de trabalho foi avaliada através de análise multivariada por meio de modelo lineares generalizados (logpoisson), sendo os resultados expressos através de razões de prevalência (RP) ajustadas e seus respectivos intervalos de 95% de confiança (IC95%). A prevalência total de acidentes no período de 12 meses foi de 25,6%. Dos tipos de acidentes referidos, o mais frequente foi a contusão ou fratura, com cerca de (10,2%) de relatos. Em seguida, aparecem as perfurações com agulha (6,5%). Os resultados da análise de correspondência revelam três grupos, destacando-se aquele formado pelos que sofreram perfuração com agulha com um perfil que abrange os auxiliares de enfermagem, trabalham no Hospital Universitário e setores adjacentes, especificamente em setores de terapia intensiva, emergência, cirurgia geral, clinica geral e ambulatório. Em relação à associação com EVPE, ter sido testemunha de agressão foi o evento mais fortemente associado com acidentes de trabalho (RP= 1,98, IC95%= 1,67; 2,34). Este estudo trouxe informações acerca da importância das características sócio-demográficas e de aspectos psicossociais na ocorrência dos acidentes de trabalho que podem ser úteis na elaboração de medidas para a prevenção desse importante problema de saúde pública.

Advantages and Versatility of Fluorescence-Based Methodology to Characterize the Functionality of LDLR and Class Mutation Assignment

Familial hypercholesterolemia (FH) is a common autosomal codominant disease with a frequency of 1:500 individuals in its heterozygous form. The genetic basis of FH is most commonly mutations within the LDLR gene. Assessing the pathogenicity of LDLR variants is particularly important to give a patient a definitive diagnosis of FH. Current studies of LDLR activity ex vivo are based on the analysis of I-125-labeled lipoproteins (reference method) or fluorescent-labelled LDL. The main purpose of this study was to compare the effectiveness of these two methods to assess LDLR functionality in order to validate a functional assay to analyse LDLR mutations. LDLR activity of different variants has been studied by flow cytometry using FITC-labelled LDL and compared with studies performed previously with I-125-labeled lipoproteins. Flow cytometry results are in full agreement with the data obtained by the I-125 methodology. Additionally confocal microscopy allowed the assignment of different class mutation to the variants assayed. Use of fluorescence yielded similar results than I-125-labeled lipoproteins concerning LDLR activity determination, and also allows class mutation classification. The use of FITC-labelled LDL is easier in handling and disposal, cheaper than radioactivity and can be routinely performed by any group doing LDLR functional validations.

Das Problem „Siebkrabben“ in der Garnelenfischerei

Along with consumption shrimp, brown shrimp fisheries also land some shrimp too small for human consumption which are sieved out on land and have to be degenerated (“crushed shrimp”). This share is recorded in German official statistics besides a third fraction called “industrial shrimp”. In view of the MSC certification processes, sustainable fishing and the fishermen’s voluntary obligation to - in future - limit the shares of “crushed shrimp”, landings data from 2010 have been analysed. Depending on seasons the goal of less than 20% of “crushed shrimp” in German landings was not met in several months in 2010, especially in August, when more than 40% of the landings contained more than the proposed amount. The processing procedures aboard the vessels are shortly discussed and the proposal is made to rather increase net selectivity than use wider sieves for the cooked fraction before landing. Cooking and processing small and later rejected shrimp is an uneconomic action. Reducing the share of “crushed shrimp” serves the idea of sustainable use of shrimp stocks as well as of sound economics.