We consider the scheduling problem of minimizing the average weighted completion time of n jobs with release dates on a single machine. We first study two linear programming relaxations of the problem, one based on a time-indexed formulation, the other on a completiontime formulation. We show their equivalence by proving that a O(n log n) greedy algorithm leads to optimal solutions to both relaxations. The proof relies on the notion of mean busy times of jobs, a concept which enhances our understanding of these LP relaxations. Based on the greedy solution, we describe two simple randomized approximation algorithms, which are guaranteed to deliver feasible schedules with expected objective value within factors of 1.7451 and 1.6853, respectively, of the optimum. They are based on the concept of common and independent a-points, respectively. The analysis implies in particular that the worst-case relative error of the LP relaxations is at most 1.6853, and we provide instances showing that it is at least e/(e - 1) 1.5819. Both algorithms may be derandomized, their deterministic versions running in O(n2 ) time. The randomized algorithms also apply to the on-line setting, in which jobs arrive dynamically over time and one must decide which job to process without knowledge of jobs that will be released afterwards.

<p>ix, [1] s., s. 1-7: sammanfattning, s. 8-142: 6 uppsatser</p> / digitalisering@umu

Infection of people with human immunodeficiency virus (HIV) as well as LPBM5 infection in mice results in progressive deterioration of the immune system in the majority of untreated hosts. Peptide immunotherapy has been shown to be effective in the stimulation or immunoregulation of T-helper 1 (TH1) and T-helper 2 (TH2) response subsets. In murine acquired immunodeficiency syndrome (AIDS), TH1 deficiency enables the host to be susceptible to coxsackievirus infection, inducing cardiopathology in a short period. T-cell receptor (TCR) Vβ8.1 peptide, a 16-mer peptide containing the entire CFR1 segment and part of the FR2 region of human Vβ8, showed both an immunoregulating and immunostimulating effect in murine AIDS. TCR Vβ8.1 peptide acts on T cells promoting interleukin-2 production and therefore enhancing a cellmediated immune response. It retarded development of cardiopathology due to coxsackievirus infection. Retrovirus infected mice treated with the peptide showed a longer life span than the nontreated retrovirus infected animals.

The purpose of this thesis work is to bring out the causes of public libraries preservation or phase-out of vinyl collections. The study in this thesis work makes a survey as a first step in figuring out what role vinyl record have at today’s public libraries as there is missing information about what the vinyl records changed status has meant for public libraries.What factors have been critical of what the public libraries have done or doing with their vinyl collections today? What role does the public library’s music responsible staff think the vinyl records have at the public library today?As a theoretic frame Taljas three different music perspective/repertoire at music libraries were used, the general education repertoire, the alternative repertoire, and the demand repertoire. The collection of the empirical material was collected with help of quantitative phone interviews. E-mails were sent to 107 public libraries asking them to take part in the study. Out of 58 replies 28 ended up participating in the study.The results showed that most libraries have had vinyl records. The factors that played a part in what the libraries had done with their vinyl collections were the following. Pro phase-out: cd records, less demand, lack of space, and move to new location.Pro preservation: cultural value, local value, and they have remained.According to the staff in charge of the music collection, the vinyl record has had a very small role in the libraries which will remain unchanged, but they do think that the vinyl record is an important upholder of culture.

Zugl.: Karlsruhe, Univ., Diss., 2006

University, Diss., 2006--Karlsruhe.

Thesis (Ph. D.)--Oregon State University, 1994. / Typescript (photocopy). Includes bibliographical references (leaves 41-45). Also available on the World Wide Web.

Universiẗat, Diss., 2002--Kiel.

Model Predictive Control (MPC) algorithms are widely applied in the chemical process industry. The main advantage of these controllers over others is their ability to provide multivariable control of the process subject to specified constraints. The presence of degrees of freedom in the plant provide an opportunity for the introduction of an optimization level (Real-Time Optimization (RTO) level), to determine optimal set points and target values for controlled variables and manipulated variables respectively, and the constraints the plant should follow to provide maximum profit. Industrial MPC controllers typically include an upper level steady-state optimizer, which usually comprises a linear programming (LP) or quadratic programming (QP) problem. This local optimizer may serve either as an integrating level between the low frequency nonlinear steady-state RTO and regulatory level, or as an independent optimizer with an economic objective function. Many researchers have reported success of LP-MPC cascade control system implementations (Sorensen and Cutler, 1998; Verne et al., 1999). However, despite its apparent success, poor LP-MPC cascade system performance and possible instability have also been reported. In particular, Shah et al. (2002) show that in the presence of a steady-state LP optimizer, the set-points could have a large variation relative to the controlled variable variation; thus the LP could degrade the MPC performance by sending highly variable set-points to the controller. Kozub (2002) indicates that in a control system with an LP steady-state optimizer, an LP instability problem may arise under certain conditions. These observations motivated research which aims to investigate the effect of the various factors on the stability and performance of the two-level LP-MPC cascade control system. Such factors include plant/model mismatch, the frequency of LP implementation, the LP objective function, constraints and type of disturbances. Since the optimization can be executed at different frequencies, two most common scenarios are considered: (i) when the LP is implemented at steady-state only and (ii) when the LP is implemented at every MPC iteration. Initially, steady-state LP optimization only is considered and it is shown that the set-points may fail to converge to constant values in the absence of external disturbances under certain conditions. Then, the effects of optimization frequency and control structure on the closed-loop properties of the LP-MPC control system are investigated. Results of a number of case studies are shown, and root causes for observed behavior discussed. As a part of the regulatory level analysis, the calculation of the closed-loop equilibrium of a process controlled by constrained MPC is studied. This problem arises in process design and operations, and is often applied within an optimization framework. It is shown that the effect of the control system on the resulting steady-state must be explicitly accounted for, and that in the general case, the use of a steady-state process model only is not sufficient for this calculation to be correctly executed. Two solution strategies, sequential and simultaneous, are presented and evaluated. The effect of high frequency noise-like disturbances on the two-level control system behavior is analyzed. The analysis which verified by case studies, showed that the LP may have an effect of amplifying the system noise through the bias term which is used for the model update. Such amplification may result in high variation of the LP set points provided to the MPC, thereby degrading the overall performance of the two-level system. / Thesis / Master of Applied Science (MASc)

Introdução: A obesidade se caracteriza como um processo oxidativo e inflamatório, que predispõe adolescentes, de modo precoce, a eventos até recentemente pouco frequentes nessa faixa etária. Assim, a ação da enzima Fosfolipase A associada às lipoproteínas (Lp-PLA ), que reduz fosfolipídios oxidados e gera lisofosfolipídios, bem como a disponibilidade de antioxidantes plasmáticos, representam um importante tema de pesquisa no contexto cardiovascular. Objetivo: Verificar se a atividade da LP-PLA 2 2 e a concentração de antioxidantes lipossolúveis se associam com os principais marcadores de risco cardiovascular em adolescentes. Métodos: Duzentos e quarenta e dois adolescentes (10 a 19 anos), de ambos os sexos foram distribuídos, segundo o índice de massa corporal (IMC), em três grupos: Eutróficos (n=77), Sobrepeso (n=82) e Obesos (n=83). A amostra foi caracterizada através de parâmetros sócio-econômicos, estado de saúde, uso de medicamentos, antedecentes familiares de doenças crônicas e prática de atividade física. Foram avaliados ainda os dados antropométricos (peso, altura e composição corporal - bioimpedância), e o consumo alimentar por meio de três recordatórios 24 h. A partir de uma amostra de sangue coletada após jejum (12h), realizaram-se as análises da atividade da Lp-PLA , LDL(-) e seus auto-anticorpos, perfil lipídico (colesterol total, LDL-C, HDL-C e triglicerídeos), tamanho da HDL, proteína transportadora de éster de colesterol (CETP), ácidos graxos não esterificados (NEFAs), adipocitocinas, assim como antioxidantes (retinol, licopeno, -tocoferol e -caroteno) no plasma. Resultados: Artigo 1: Lp-PLA maybe an important cardiovascular biomarker in obese adolescents. Verificou-se que o perfil lipídico, insulina, HOMA-IR (resistência à insulina) e LDL(-) evidenciaram um maior risco cardiovascular nos adolescentes obesos. A atividade da enzima Lp-PLA 2 mostrou uma variação proporcional ao IMC, circunferência da cintura e porcentagem de gordura. Essa tendência foi, ainda, reforçada pelas associações positivas entre a enzima e HOMA-IR, glicose, insulina e as variáveis lipídicas. Adicionalmente, associação negativa foi encontrada para ApoAI. As associações mais relevantes foram observadas para ApoB e Apo B / Apo AI (=0,293; P<0,001, =0,343; P<0,001, respectivamente). O melhor modelo preditor para a atividade da enzima incluiu Apo B/Apo AI (= 0,327; P<0,001), tamanho da HDL (=-0,326; P<0,001), circunferência da cintura (=0,171; P=0,006) e glicose (= 0,119; P=0,038). A análise de Odds Ratio mostrou que a mudança de uma unidade na razão entre Apo B/Apo AI esteve associada a 73.5 maior risco para elevada atividade de Lp-PLA 2 . Conclusão: A enzima Lp-PLA , em adolescentes, varia em função do estado nutricional e está relacionada a vários marcadores de risco cardiovascular, especialmente a Apo B/Apo AI. Assim, a atividade da enzima pode representar um importante biomarcador de risco cardiovascular na adolescência. Artigo 2: Antioxidant, and inflammatory aspects of phospholipase A 2 associated to lipoprotein (Lp-PLA ): A review. Esta revisão descreve os principais aspectos relacionados à enzima Lp-PLA 2 e seu impacto no perfil inflamatório e oxidativo da doença aterosclerótica. Artigo 3: Plasma antioxidants, but not the dietary ones, are associated with cardiometabolic risk in adolescents. Neste artigo, observou-se que 2 os antioxidantes -caroteno, licopeno, retinol e -tocoferol variam em função do IMC. Verificou-se que -caroteno e -tocoferol apresentaram valores reduzidos para o grupo obeso em comparação ao eutrófico e ao sobrepeso. Para o -caroteno, verificou-se que essa diferença pôde ser observada inclusive quando comparados sobrepesos e eutróficos. Quando esses antioxidantes foram ajustados pelo colesterol total ou pelo LDL-C essas diferenças se mantiveram. Correlações importantes foram obtidas entre os antioxidantes ajustados por colesterol ou por LDL-C e as variáveis de risco cardiometabólico (perfil lipídico (colesterol total e frações, CETP), resistência à insulina (HOMA-IR, insulina, glicose) e LDL(-)). A obesidade representou um importante fator para a existência dessas correlações, pois após o ajuste por IMC foram reduzidas. Apesar desses resultados, os antioxidantes availados pelo recordatório de 24h não apresentaram nenhuma correlação com os fatores de risco cardiometabólico. Conclusão: Antioxidantes plasmáticos estão relacionados ao risco cardiometabólico em adolescentes, sendo que o IMC desempenha um papel importante para a existência dessas correlações. Tais biomarcadores representam uma melhor maneira de estimar a influência de um padrão dietético sobre o risco cardiometabólico em adolescentes do que a avaliação do inquérito alimentar / Introduction: Obesity is characterized as an oxidative and inflammatory process, which precociously predisposes adolescents to events until recently uncommon in this age group. Thus, the action of Lipoprotein-associated phospholipase A (LpPLA ), which reduces oxidized phospholipids and generates lysophospholipids, as well as the availability of plasma antioxidants, represent important subjects of cardiovascular research. Objetive: To evaluate if the activity of Lp-PLA 2 and the concentration of fat-soluble antioxidants are associated with the most important cardiovascular risk markers in adolescents. Methods: 242 adolescents (10 to 19 years old), from both sexes, were distributed according to Body mass index (BMI) in three groups: Health Weigth (HW, n=77), Overweigth (OV, n=82) and Obeses (OB, n=83). The sample was characterized by socioeconomic parameters, health condition, use of medications, family history of chronic diseases and physical activity. It were evaluated also the anthropometric data (weigth, heigth, body composition - bioimpedance) and the food intake through three 24h-recall. From a blood sample collected after fasting (12h), were analized the Lp-PLA activity, the levels of LDL(-) and it antibodies, the lipid profile (total cholesterol, LDL-C, HDL-C and triglycerides), HDL-size, Non-Esterified Fatty Acids (NEFAs), Cholesteryl Ester Transfer Protein (CETP), adipocytokines, as well as plasma antioxidants (retinol, licopene, -tocopherol e -carotene). Results: Article 1: Lp-PLA as an important biomarker of cardiovascular risk in obese adolescents. It was observed that the lipid profile, the insulin, the HOMA-IR (insulin resistance) and the LDL(-) represented a higher cardiovascular risk in obese adolescents. The activity of Lp-PLA 2 has shown a variation proportional to BMI, waist circumference and fat mass percentage. This tendency was reinforced by positive associations of the enzyme with HOMA-IR, glucose, insulin and lipid variables. Additionaly, a negative association was observed for Apo AI. The most relevant associations were observed for ApoB and Apo B / Apo AI (=0,293; P<0,001, =0,343; P<0,001, respectively). The best predictor model for the enzyme activity included Apo B/Apo AI (= 0,327; P<0,001), HDLsize (=-0,326; P<0,001), waist circumference (=0,171; P=0,006) and glucose (= 0,119; P=0,038). The Odds Ratio analysis showed that the change of one unit in the ratio of Apo B/Apo AI was related to a 73.5 times higher risk of elevated Lp-PLA activity. Conclusion: The enzyme Lp-PLA , in adolescents, varies in function of the nutritional status and it is related to several cardiovascular risk markers, especially to Apo B/Apo AI. Thus, this enzyme activity may represent an important biomarker of cardiovascular risk in adolescence. Article 2: Antioxidant and inflammatory aspects of phospholipase A 2 2 associated to lipoprotein (Lp-PLA ): a review. This review describes the main aspects related to the enzime Lp-PLA 2 and its impact to inflammatory and oxidative profiles of atherosclerotic disease. Article 3: Plasma antioxidants, but not the dietary ones, are associated with cardiometabolic risk in 2 adolescents. It was observed that the antioxidants -carotene, licopene, retinol and -tocopherol vary in function of BMI. It was verified that -carotene and - tocopherol presented reduced values for the OB group in comparison with the HW and OV groups. For -carotene, it was observed that this difference was also verified when OB and OV were compared. These differences remained alike when the antioxidants were adjusted by total cholesterol or by LDL-C. Important correlations were obtained between the antioxidants adjusted by total cholesterol or by LDL-C, and cardiometabolic risk variables (lipid profile (total cholesterol and fractions, CETP), insulin resistance (HOMA-IR, insulin, glucose) and LDL(-)). The obesity represented an important factor to the occurrence of these correlations, since they were reduced after BMI adjustment. Despite these results, the antioxidants evaluated by 24h-diet recall did not show any correlations with cardiometabolic risk. Conclusion: Plasma antioxidants are related to cardiometabolic risk in adolescents, where the BMI represents an important factor. These biomarkers are better than the food intake to estimate the influence of a dietary pattern on the cardiometabolic risk in adolescents