Determinants of exercise capacity in patients with type 2 diabetes

OBJECTIVE - Type 2 diabetes is associated with reduced exercise capacity, but the cause of this association is unclear. We sought the associations of impaired exercise capacity in type 2 diabetes. RESEARCH DESIGN AND METHODS - Subclinical left ventricular (LV) dysfunction was sought from myocardial strain rate and the basal segmental diastolic velocity (Em) of each wall in 170 patients with type 2 diabetes (aged 56 +/- 10 years, 91 men), good quality echocardiographic images, and negative exercise echocardiograms. The same measurements were made in 56 control subjects (aged 53 +/- 10 years, 29 men). Exercise capacity was calculated in metabolic equivalents, and heart rate recovery (HRR) was measured as the heart rate difference between peak and 1 min after exercise. In subjects with type 2 diabetes, exercise capacity was correlated with clinical, therapeutic, biochemical, and echocardiographic variables, and significant independent associations were sought using a multiple linear regression model. RESULTS - Exercise capacity, strain rate, Em, and HRR were significantly reduced in type 2 diabetes. Exercise capacity was associated with age (r- = -0.37, P < 0.001), male sex (r = 0.26, P = 0.001), BMI (r = -0.19, P = 0.012), HbA(1c) (AlC; r = -0.22, P = 0.009), Em (r = 0.43, P < 0.001), HRR (r = 0.42, P < 0.001), diabetes duration (r = -0.18, P = 0.021), and hypertension history (r = -0.28, P < 0.001). Age (P < 0.001), male sex (P = 0.007), BMI (P = 0.001), Em (P = 0.032), HRR (P = 0.013), and AlC (P = 0.0007) were independent predictors of exercise capacity. CONCLUSIONS - Reduced exercise capacity in patients with type 2 diabetes is associated with diabetes control, subclinical LV dysfunction, and impaired HRR.

Oxygen Utilization and Downward Carbon Flux in an Oxygen-Depleted Eddy in the Eastern Tropical North Atlantic

The occurrence of mesoscale eddies that develop suboxic environments at shallow depth (about 40-100 m) has recently been reported for the eastern tropical North Atlantic (ETNA). Their hydrographic structure suggests that the water mass inside the eddy is well isolated from ambient waters supporting the development of severe near-surface oxygen deficits. So far, hydrographic and biogeochemical characterization of these eddies was limited to a few autonomous surveys, with the use of moorings, under water gliders and profiling floats. In this study we present results from the first dedicated biogeochemical survey of one of these eddies conducted in March 2014 near the Cape Verde Ocean Observatory (CVOO). During the survey the eddy core showed oxygen concentrations as low as 5 µmol kg-1 with a pH of around 7.6 at approximately 100 m depth. Correspondingly, the aragonite saturation level dropped to 1 at the same depth, thereby creating unfavorable conditions for calcifying organisms. To our knowledge, such enhanced acidity within near-surface waters has never been reported before for the open Atlantic Ocean. Vertical distributions of particulate organic matter and dissolved organic matter (POM and DOM), generally showed elevated concentrations in the surface mixed layer (0-70 m), with DOM also accumulating beneath the oxygen minimum. With the use of reference data from the upwelling region where these eddies are formed, the oxygen utilization rate was calculated by determining oxygen consumption through the remineralization of organic matter. Inside the core, we found these rates were almost 1 order of magnitude higher (apparent oxygen utilization rate (aOUR); 0.26 µmol kg-1 day-1) than typical values for the open North Atlantic. Computed downward fluxes for particulate organic carbon (POC), were around 0.19 to 0.23 g C m-2 day-1 at 100 m depth, clearly exceeding fluxes typical for an oligotrophic open-ocean setting. The observations support the view that the oxygen-depleted eddies can be viewed as isolated, westwards propagating upwelling systems of their own, thereby represent re-occurring alien biogeochemical environments in the ETNA.

A study on the effect of functional distribution of income on aggregate demand

In this thesis, we study the causal relationship between functional distribution of income and economic growth. In particular, we focus on some of the aspects that might alter the effect of the profit share on growth. After a brief introduction and literature review, the empirical contributions will be presented in Chapters 3,4 and 5. Chapter 3 analyses the effect of a contemporaneous decrease in the wage share among countries that are major trade partners. Falling wage share and wage moderation are a global phenomenon which are hardly opposed by governments. This is because lower wages are associated with lower export prices and, therefore, have a positive effect on net-exports. There is, however, a fallacy of composition problem: not all countries can improve their balance of payments contemporaneously. Studying the country members of the North America Free Trade Agreement, we find that the effect on export of a contemporaneous decrease in the wage share in Mexico, Canada and the United States, is negative in all countries. In other words, the competitive advantage that each country gains because of a reduction in its wage share (to which is associated a decrease in export prices), is offset by a contemporaneous increase in competitiveness in the other two countries. Moreover, we find that NAFTA is overall wage-led: the profit share has a negative effect on aggregate demand. Chapter 4 tests whether it is possible that the effect of the profit share on growth is different in the long run and in the short run. Following Blecker (2014) our hypothesis is that in the short run the growth regime is less wage-led than it is in the long run. The results of our empirical investigation support this hypothesis, at least for the United States over the period 1950-2014. The effect of wages on consumption increases more than proportionally compared to the effect of profits on consumption from the short to the long run. Moreover, consumer debt seem to have only a short-run effect on consumption indicating that in the long run, when debt has to be repaid, consumption depends more on the level of income and on how it is distributed. Regarding investment, the effect of capacity utilization is always larger than the effect of the profit share and that the difference between the two effects is higher in the long run than in the short run. This confirms the hypothesis that in the long run, unless there is an increase in demand, it is likely that firms are not going to increase investments even in the presence of high profits. In addition, the rentier share of profits – that comprises dividends and interest payments – has a long-run negative effect on investment. In the long run rentiers divert firms’ profits from investment and, therefore, it weakens the effect of profits on investment. Finally, Chapter 5 studies the possibility of structural breaks in the relationship between functional distribution of income and growth. We argue that, from the 1980s, financialization and the European exchange rate agreements weakened the positive effect of the profit share on growth in Italy. The growth regime is therefore becoming less profit-led and more wage-led. Our results confirm this hypothesis and also shed light on the concept of cooperative and conflictual regimes as defined by Bhaduri and Marglin (1990).

Human leukemia inhibitory factor upregulates LDL receptors on liver cells and decreases serum cholesterol in the cholesterol-fed rabbit

In a previous study, we found that the cytokine (human) leukemia inhibitory factor (hLIF) significantly reduced plasma cholesterol levels and the accumulation of lipid in aortic tissues of cholesterol-fed rabbits after 4 weeks of treatment. The mechanisms by which this occurs were investigated in the present study. This involved examining the effect of hLIF on (1) the level of plasma cholesterol at different times throughout the 4-week treatment and diet period; (2) smooth muscle cell (SMC) and macrophage-derived foam cell formation in vitro; and (3) LDL receptor expression and uptake in the human hepatoma cell line HepG2. At time zero, an osmotic minipump (2-mL capacity; infusion rate, 2.5 mu L/h; 28 days) containing either hLIF (30 mu g.kg(-1).d(-1)) or saline was inserted into the peritoneal cavity of New Zealand White rabbits (N=24). Rabbits were divided into four groups of six animals each. Group 1 received a normal diet/saline; group 2, a normal diet/hLIF; group 3, a 1% cholesterol diet/saline; and group 4, a 1% cholesterol diet/hLIF. hLIF had no effect on the plasma lipids or artery wall of group 2 rabbits (normal diet). However, in group 4 rabbits, plasma cholesterol levels and the percent surface area of thoracic aorta covered by fatty streaks was decreased by approximate to 30% and 80%, respectively, throughout all stages of the 4-week treatment period. In vitro, hLIF failed to prevent lipoprotein uptake by either SMCs or macrophages (foam cell formation) when the cells were exposed to P-VLDL for 24 hours. In contrast, hLIF (100 ng/mL) added to cultured human hepatoma HepG2 cells induced a twofold or threefold increase in intracellular lipid accumulation in the medium containing 10% lipoprotein-deficient serum or 10% fetal calf serum, respectively. This was accompanied by a significant non-dose-dependent increase in LDL receptor expression in hLIF-treated HepG2 cells incubated with LDL (20 mu g/mL) when compared with controls (P

Estudo comparativo entre o sistema convencional de arrefecimento e o arrefecedor evaporativo para os edifícios industriais portugueses

Em Portugal existem muitos espaços comerciais e industriais em que as necessidades térmicas de arrefecimento são muito superiores às necessidades de aquecimento devido aos ganhos internos que advêm da existência de equipamentos e da iluminação dos edifícios, assim como, da presença das pessoas. A instalação de sistemas convencionais de ar condicionado para espaços comerciais e industriais de grande dimensão está geralmente associada ao transporte de grandes caudais de ar, e consequentemente, a elevados consumos de energia primária, e também, elevados custos de investimento, de manutenção e de operação. O arrefecedor evaporativo é uma solução de climatização com elevada eficiência energética, cujo princípio de funcionamento promove a redução do consumo de energia primária nos edifícios. A metodologia utilizada baseou-se na criação de uma ferramenta informática de simulação do funcionamento de um protótipo de um arrefecedor evaporativo. Foi efetuada a modelação matemática das variáveis dinâmicas envolvidas, dos processos de transferência de calor e de massa, assim como dos balanços de energia que ocorrem no arrefecedor evaporativo. A ferramenta informática desenvolvida permite o dimensionamento do protótipo do arrefecedor evaporativo, sendo determinadas as caraterísticas técnicas (potência térmica, caudal, eficiência energética, consumo energético e consumo e água) de acordo com o tipo de edifício e com as condições climatéricas do ar exterior. Foram selecionados três dimensionamentos de arrefecedores evaporativos, representativos de condições reais de uma gama baixa, média e elevada de caudais de ar. Os resultados obtidos nas simulações mostram que a potência de arrefecimento (5,6 kW, 16,0 kW e 32,8 kW) e o consumo de água (8 l/h, 23,9 l/h e 48,96 l/h) aumentam com o caudal de ar do arrefecedor, 5.000 m3/h, 15.000 m3/h e 30.000 m3/h, respetivamente. A eficácia de permuta destes arrefecedores evaporativos, foi de 69%, 66% e 67%, respetivamente. Verificou-se que a alteração de zona climática de V1 para V2 implicou um aumento de 39% na potência de arrefecimento e de 20% no consumo de água, e que, a alteração de zona climática de V2 para V3 implicou um aumento de 39% na potência de arrefecimento e de 39% no consumo de água. O arrefecedor evaporativo apresenta valores de consumo de energia elétrica entre 40% a 80% inferiores aos dos sistemas de arrefecimento convencionais, sendo este efeito mais intenso quando a zona climática de verão se torna mais severa.

Melhoria de linha de produção na indústria automóvel

No âmbito da unidade curricular Dissertação do 2ºano do Mestrado em Engenharia mecânica – Ramo de Gestão Industrial do Instituto Superior de Engenharia do Porto, o presente trabalho de dissertação foi enquadrado num projeto industrial para a racionalização de uma linha de produção. O projeto foi desenvolvido numa empresa de produção de componentes por alumínio injetado e seguidamente processos de maquinação, para mercados a nível mundial destinados à indústria automóvel. A realização deste projeto teve como objetivo a melhoria de uma linha de produção na empresa TESCO Componentes para automóveis, Lda. recorrendo a métodos e ferramentas utilizadas pela Gestão Industrial tais como, Lean, 5’S, PDCA assim como ferramentas específicas de balanceamento e otimização de linhas. Os métodos e ferramentas utilizados permitiram a seleção da linha, a definição e caraterização do modelo em produção e posto de trabalho, isto com o objetivo reduzir os custos, aumentar a produtividade e conduzir a melhorias ao nível de qualidade. Através de análises realizadas aos dados de produção foi possível a avaliação do indicador de eficiência operacional do equipamento, através dos OEE’s, o que possibilitou uma análise mais compreensiva da capacidade e cadência da linha de produção. Com a aplicação dos métodos ligados à filosofia de produção em Lean, foi possível atingir-se os objetivos inicialmente definidos, e em alguns casos foi possível ultrapassá-los. Em função da abordagem integrada que foi seguida, conseguiu-se uma redução de um posto de trabalho, traduzindo-se na redução do custo de fabrico não deixando de referir que também houve melhorias a nível de qualidade do produto. Reduzindo a possibilidade de falhas com as especificações estabelecidas pelos clientes. Como efeito positivo deste projeto pode-se apontar o fato de que a empresa Tesco Componentes para Automóveis, Lda. aumentou a sua competitividade com a oportunidade de redução do preço final do produto e também com o aumento da qualidade do mesmo.

Cancelamentos de cirurgias no próprio dia

RESUMO - INTRODUÇÃO: Para garantir a qualidade e universalidade dos cuidados de Saúde, é fundamental, que os recursos disponíveis sejam bem utilizados, evitando desperdícios. Os resultados de um hospital estão diretamente ligados aos resultados do Bloco Operatório. A taxa de utilização e a taxa de cancelamentos são indicadores da atividade dos Blocos Operatórios. Realizou-se um estudo piloto no Hospital Dr. José de Almeida em Cascais. OBJECTIVO: Conhecer as taxas de cancelamento de cirurgias no próprio dia. METODOLOGIA: Estudo descritivo longitudinal, retrospectivo, quantitativo, às cirurgias agendadas, entre 1 de Janeiro e 31 de Março de 2012. Utilizou-se a estatística descritiva e a inferência estatística através de testes de independência de variáveis. RESULTADOS: 1524 cirurgias agendadas, canceladas 205, com 100 cancelamentos no próprio dia. Os resultados revelam na globalidade taxas de cancelamento (13,45%) inferiores às fornecidas pelo Ministério da Saúde em relação a 2008, 2009 e 2010, com 28,4%, 26,0% e 26,6% respectivamente. No entanto, as taxas de cancelamento no próprio dia são semelhantes 48,78% no estudo e, entre 44,1% e 50,5% nos dados do Ministério da Saúde. Os estudos internacionais consultados revelam taxas globais de 0,34% na China (Sung,2010) num hospitalar multidisciplinar e 30,3% (taxa de cancelamentos no dia) na Índia (Garg, 2009). CONCLUSÃO: A imputação do motivo de cancelamento é feita ao “serviço/ hospital” ou a “outros”, o utente apresenta uma taxa baixa de imputação do motivo de cancelamento. Foi encontrada uma relação de dependência entre as variáveis, com exceção da relação entre data do cancelamento e a especialidade cirúrgica. Assim, considera-se pertinente a realização de um estudo mais aprofundado e abrangente deste fenómeno nas instituições de saúde em Portugal.

Tempos de espera cirúrgicos: situação em Portugal e determinantes

RESUMO - Objectivos Um dos problemas mais comuns nos sistemas de saúde e particularmente naqueles que têm uma estrutura predominantemente pública são os elevados Tempos Espera (TE) para cirurgia. Este projecto tem como principal objectivo identificar a importância relativa em Portugal das determinantes do TE cirúrgico. Metodologia Para clarificar essa importância, aplicou-se um questionário desenvolvido pelo Fraser Institute, utilizado para a análise anual dos TE no Canadá, recorrendo a um painel de peritos e através da realização da técnica Delphi, procurou-se consensualizar quais as determinantes das Listas Espera (LE), mais importantes. Para ilustrar a diversidade de perspectivas, recorreu-se também à análise de trabalhos realizados por inúmeras organizações, onde pudemos observar e recolher distintas abordagens, políticas e técnicas da questão das LE em países com diferentes tipos de sistemas de saúde. Resultados Os resultados obtidos revelam que os peritos consideraram a disponibilidade de tempo no Bloco Operatório (BO) e a de anestesiologistas, como as determinantes com maior impacto no aumento das LE. Conclusões Dos dados recebidos relativos ao Sistema Integrado Gestão Inscritos Cirurgia (SIGIC), bem como dos retirados de relatórios oficiais, concluímos que as LE cirúrgicas tiveram evolução positiva, nomeadamente na redução da mediana do TE da Lista Inscritos Cirurgia (LIC) (meses), no entanto, os objectivos dos Tempos Máximos Resposta Garantidos (TMRG) não estão a ser cumpridos. A análise das diferentes iniciativas e estratégias políticas para combater as LE, permitiu-nos sugerir caminhos a explorar, tendo como objectivo minorar o problema das LE: cuidados integrados, optimização da eficiência na utilização da capacidade instalada e maior aposta na cirurgia de ambulatório.

Coronary arteriography rates in Switzerland: how do they vary?

Coronary heart disease is a leading cause of death for both sexes in developed countries. Controversy has arisen about the health benefits and risks of coronary surgery and, more recently of coronary angioplasty. As a clinical prerequisite to these interventions, coronary arteriography can be considered an indicator of invasive services offered to coronary heart disease patients. We collected data on characteristics of all patients subjected to coronary arteriography during 1984 in Switzerland. A total of 4921 coronary arteriographies were performed among 4359 patients; this corresponds to 77 procedures/100,000 residents and 68 patients/100,000 residents. Rates for men are 4.2 times women's rates, and the highest utilization rate for both sexes are observed in the group aged 40-64. Large variations characterize cantonal and regional coronary arteriography rates. Similarly, the distribution of centers practising this procedure is not uniform. These observations are placed in the context of the general practice of coronary angiography, changes expected in the face of by-pass surgery and angioplasty expansion, and coronary heart disease data.

Rules of origin : from analysis to reform

General Introduction This thesis can be divided into two main parts :the first one, corresponding to the first three chapters, studies Rules of Origin (RoOs) in Preferential Trade Agreements (PTAs); the second part -the fourth chapter- is concerned with Anti-Dumping (AD) measures. Despite wide-ranging preferential access granted to developing countries by industrial ones under North-South Trade Agreements -whether reciprocal, like the Europe Agreements (EAs) or NAFTA, or not, such as the GSP, AGOA, or EBA-, it has been claimed that the benefits from improved market access keep falling short of the full potential benefits. RoOs are largely regarded as a primary cause of the under-utilization of improved market access of PTAs. RoOs are the rules that determine the eligibility of goods to preferential treatment. Their economic justification is to prevent trade deflection, i.e. to prevent non-preferred exporters from using the tariff preferences. However, they are complex, cost raising and cumbersome, and can be manipulated by organised special interest groups. As a result, RoOs can restrain trade beyond what it is needed to prevent trade deflection and hence restrict market access in a statistically significant and quantitatively large proportion. Part l In order to further our understanding of the effects of RoOs in PTAs, the first chapter, written with Pr. Olivier Cadot, Celine Carrère and Pr. Jaime de Melo, describes and evaluates the RoOs governing EU and US PTAs. It draws on utilization-rate data for Mexican exports to the US in 2001 and on similar data for ACP exports to the EU in 2002. The paper makes two contributions. First, we construct an R-index of restrictiveness of RoOs along the lines first proposed by Estevadeordal (2000) for NAFTA, modifying it and extending it for the EU's single-list (SL). This synthetic R-index is then used to compare Roos under NAFTA and PANEURO. The two main findings of the chapter are as follows. First, it shows, in the case of PANEURO, that the R-index is useful to summarize how countries are differently affected by the same set of RoOs because of their different export baskets to the EU. Second, it is shown that the Rindex is a relatively reliable statistic in the sense that, subject to caveats, after controlling for the extent of tariff preference at the tariff-line level, it accounts for differences in utilization rates at the tariff line level. Finally, together with utilization rates, the index can be used to estimate total compliance costs of RoOs. The second chapter proposes a reform of preferential Roos with the aim of making them more transparent and less discriminatory. Such a reform would make preferential blocs more "cross-compatible" and would therefore facilitate cumulation. It would also contribute to move regionalism toward more openness and hence to make it more compatible with the multilateral trading system. It focuses on NAFTA, one of the most restrictive FTAs (see Estevadeordal and Suominen 2006), and proposes a way forward that is close in spirit to what the EU Commission is considering for the PANEURO system. In a nutshell, the idea is to replace the current array of RoOs by a single instrument- Maximum Foreign Content (MFC). An MFC is a conceptually clear and transparent instrument, like a tariff. Therefore changing all instruments into an MFC would bring improved transparency pretty much like the "tariffication" of NTBs. The methodology for this exercise is as follows: In step 1, I estimate the relationship between utilization rates, tariff preferences and RoOs. In step 2, I retrieve the estimates and invert the relationship to get a simulated MFC that gives, line by line, the same utilization rate as the old array of Roos. In step 3, I calculate the trade-weighted average of the simulated MFC across all lines to get an overall equivalent of the current system and explore the possibility of setting this unique instrument at a uniform rate across lines. This would have two advantages. First, like a uniform tariff, a uniform MFC would make it difficult for lobbies to manipulate the instrument at the margin. This argument is standard in the political-economy literature and has been used time and again in support of reductions in the variance of tariffs (together with standard welfare considerations). Second, uniformity across lines is the only way to eliminate the indirect source of discrimination alluded to earlier. Only if two countries face uniform RoOs and tariff preference will they face uniform incentives irrespective of their initial export structure. The result of this exercise is striking: the average simulated MFC is 25% of good value, a very low (i.e. restrictive) level, confirming Estevadeordal and Suominen's critical assessment of NAFTA's RoOs. Adopting a uniform MFC would imply a relaxation from the benchmark level for sectors like chemicals or textiles & apparel, and a stiffening for wood products, papers and base metals. Overall, however, the changes are not drastic, suggesting perhaps only moderate resistance to change from special interests. The third chapter of the thesis considers whether Europe Agreements of the EU, with the current sets of RoOs, could be the potential model for future EU-centered PTAs. First, I have studied and coded at the six-digit level of the Harmonised System (HS) .both the old RoOs -used before 1997- and the "Single list" Roos -used since 1997. Second, using a Constant Elasticity Transformation function where CEEC exporters smoothly mix sales between the EU and the rest of the world by comparing producer prices on each market, I have estimated the trade effects of the EU RoOs. The estimates suggest that much of the market access conferred by the EAs -outside sensitive sectors- was undone by the cost-raising effects of RoOs. The chapter also contains an analysis of the evolution of the CEECs' trade with the EU from post-communism to accession. Part II The last chapter of the thesis is concerned with anti-dumping, another trade-policy instrument having the effect of reducing market access. In 1995, the Uruguay Round introduced in the Anti-Dumping Agreement (ADA) a mandatory "sunset-review" clause (Article 11.3 ADA) under which anti-dumping measures should be reviewed no later than five years from their imposition and terminated unless there was a serious risk of resumption of injurious dumping. The last chapter, written with Pr. Olivier Cadot and Pr. Jaime de Melo, uses a new database on Anti-Dumping (AD) measures worldwide to assess whether the sunset-review agreement had any effect. The question we address is whether the WTO Agreement succeeded in imposing the discipline of a five-year cycle on AD measures and, ultimately, in curbing their length. Two methods are used; count data analysis and survival analysis. First, using Poisson and Negative Binomial regressions, the count of AD measures' revocations is regressed on (inter alia) the count of "initiations" lagged five years. The analysis yields a coefficient on measures' initiations lagged five years that is larger and more precisely estimated after the agreement than before, suggesting some effect. However the coefficient estimate is nowhere near the value that would give a one-for-one relationship between initiations and revocations after five years. We also find that (i) if the agreement affected EU AD practices, the effect went the wrong way, the five-year cycle being quantitatively weaker after the agreement than before; (ii) the agreement had no visible effect on the United States except for aone-time peak in 2000, suggesting a mopping-up of old cases. Second, the survival analysis of AD measures around the world suggests a shortening of their expected lifetime after the agreement, and this shortening effect (a downward shift in the survival function postagreement) was larger and more significant for measures targeted at WTO members than for those targeted at non-members (for which WTO disciplines do not bind), suggesting that compliance was de jure. A difference-in-differences Cox regression confirms this diagnosis: controlling for the countries imposing the measures, for the investigated countries and for the products' sector, we find a larger increase in the hazard rate of AD measures covered by the Agreement than for other measures.

Transgenic reexpression of GLUT1 or GLUT2 in pancreatic beta cells rescues GLUT2-null mice from early death and restores normal glucose-stimulated insulin secretion.

GLUT2-null mice are hyperglycemic, hypoinsulinemic, hyperglucagonemic, and glycosuric and die within the first 3 weeks of life. Their endocrine pancreas shows a loss of first phase glucose-stimulated insulin secretion (GSIS) and inverse alpha to beta cell ratio. Here we show that reexpression by transgenesis of either GLUT1 or GLUT2 in the pancreatic beta cells of these mice allowed mouse survival and breeding. The rescued mice had normal-fed glycemia but fasted hypoglycemia, glycosuria, and an elevated glucagon to insulin ratio. Glucose tolerance was, however, normal. In vivo, insulin secretion assessed following hyperglycemic clamps was normal. In vitro, islet perifusion studies revealed that first phase of insulin secretion was restored as well by GLUT1 or GLUT2, and this was accompanied by normalization of the glucose utilization rate. The ratio of pancreatic insulin to glucagon and volume densities of alpha to beta cells were, however, not corrected. These data demonstrate that 1) reexpression of GLUT1 or GLUT2 in beta cells is sufficient to rescue GLUT2-null mice from lethality, 2) GLUT1 as well as GLUT2 can restore normal GSIS, 3) restoration of GSIS does not correct the abnormal composition of the endocrine pancreas. Thus, normal GSIS does not depend on transporter affinity but on the rate of uptake at stimulatory glucose concentrations.

A Generalized Model Study of Scour Around Bridge Piers and Abutments, HR-24, 1953

Four classes of variables are apparent in the problem of scour around bridge piers and abutments--geometry of piers and abutments, stream-flow characteristics, sediment characteristics, and geometry of site. The laboratory investigation, from its inception, has been divided into four phases based on these classes. In each phase the variables in three of the classes are held constant and those in the pertinent class are varied. To date, the first three phases have been studied. Typical scour bole patterns related to the geometry of the pier or abutment have been found. For equilibrium conditions of scour with uniform sand, the velocity of flow and the sand size do not appear to have any measurable effects on the depth of scour. This result is especially encouraging in the search for correlation between model and prototype since it would indicate that, primarily, only the depth of flow might be involved in the scale effect. The technique of model testing has been simplified, therefore, because rate of sediment transportation does not need to be scaled. Prior to the establishment of equilibrium conditions, however, depths of scour in excess of those for equilibrium conditions have been found. A concept of active scour as an imbalance between sediment transport capacity and rate of sediment supply has been used to explain the laboratory observations.

Raaka-aine- ja energiatehokkuuden parantaminen Oras Oy:n valimossa

Tämän diplomityön tavoitteena oli tutkia toimintatapoja ja edellytyksiä parantaa Oras Oy:n valimon raaka-aine- ja energiatehokkuutta. Tarkastelu suoritettiin ekotehokkuusajattelun näkökulmasta. Valimon ekotehokkuutta mitattiin metallin saannon sekä valu-uunien energiatehokkuuden avulla. Tutkimustyö suoritettiin valitsemalla tarkastelun kohteeksi 20 valutuotetta. Metallin saantoa selvitettäessä punnittiin tuotteita eri työvaiheissa,jolloin saatiin selville valukanavien sekä koneistus- ja hiontavarojen osuudet valutuotteisiin panostetusta messingistä. Saantoa laskettaessa tuli myös huomioida vuosittain hylättävien tuotteiden määrät sekä messingin raaka-ainekierto kokonaisuudessaan. Valu-uunien osalta selvitettiin toiminta-ajan ja energiankulutuksen jakautuminen messingin sulattamisen ja sulan kuumanapidon kesken. Työssä tarkasteltiin, kuinka paljon metallin saantoa voitaisiin parantaa pienentämällä valukanavien ja työvarojen osuutta valoksissa sekä vähentämällähylkyjen määrää. Lisäksi tarkasteltiin muutosten vaikutuksia raaka-ainekustannuksiin sekä jätteiden määrään. Valu-uunien energiatehokkuuden parantamisen osaltatarkasteltiin käyttöasteen nostamisen eli viikoittaisen käyntiajan lisäämisen vaikutuksia energiankulutukseen ja -kustannuksiin sekä edellytyksiä pitää osa uuneista kylmänä.

Kytkentäisen lähiverkon palvelutason mittaaminen

Tässä diplomityössä tutkittiin yrityksen Ethernet-lähiverkon palvelutasoa, palveluiden saatavuuden näkökulmasta. Tutkimus pohjautui käytännön tarpeeseen. Palvelun saatavuuteen verkon osalta vaikuttavat sen käyttöaste, virheet ja viiveet. Työssä käytettiin valmiita kaupallisia ohjelmia verkon hallintaan ja verkkostatistiikan keräämiseen. Työssä selvitettiin teoriapohjaa laitteiden, kytkentätekniikoiden, palvelulaatuprotokollien (QoS), tietoliikenneprotokollien, RMON:in, SNMP:in ja VLAN:in osalta, jotka yhdessä muodostavat kytkentäisen lähiverkon palvelutason. Työn tuloksena todettiin mittauskohteena olevan lähiverkon palvelutason olevan hyvällä tasolla. Työn tuloksista pääteltiin tulevaisuuden suurimpana haasteena olevan lähiverkkoja yhdistävien yhteyksien nostaminen selvästi paremmalle suoritustasolle. Lähiverkkojen teoreettinen suorituskyky onkin useimmiten riittävä, mutta lähiverkkojen hallinnassa on parantamisen varaa. Työssä toteutettiin seurantajärjestelmä, jolla on helppo seurata lähiverkon palvelutason kehitystä jatkossa.

Tuotannon läpäisyajan analyysi

Diplomityö on tapaustutkimus, jossa analysoidaan yrityksen tilausohjautuvan massatuotannon läpimenoon vaikuttavia tekijöitä huippukuormituksen aikana. Tavoitteena oli selvittää päätuotantolinjan yksittäisten osien kapasiteetin käyttösuhdetta pienentävät ja koko tuotantoketjun läpäisyaikaan vaikuttavat tekijät, kapasiteetin käyttösuhdetta pienentävien tekijöiden poistamiseksi tarvittavat toimenpiteet ja teoreettinen maksimikapasiteetti näiden toimenpiteiden suorittamisen jälkeen. Selvitystä käytettiin tukimateriaalina päätettäessä tulevaisuuden laiteinvestoinneista. Projektin tiedonkeruun menetelminä toteutettiin osallistuvaa havainnointia, tehtiin aikamittauksia sekä kokeiltiin erilaisia tuotannonohjauksen järjestelyjä. Kerättyjen tietojen pohjalta laadittiin arviolaskelmia kapasiteetin käyttösuhteen määrittämiseksi sekä arvioitiin eri muuttujien vaikutusta. Tutkimuksen perusteella löydettiin kustakin päätuotantolinjan työvaiheesta kapasiteetin käyttösuhdetta vähentäviä tekijöitä ja laadittiin parannusehdotuksia. Esimerkkeinä työaikajärjestelyt ja käyttömiesten toimenkuvaan kuuluvien tehtävien järjestelyt, sekä kunnossapidon, tuotannonohjauksen ja tiedonkulun kehittäminen. Tutkimuksessa esitettyjen parannusehdotusten, kysynnän kehitysennusteiden ja suunnitellun laitteistoinvestoinnin toteutumisen myötä tuotannon pullonkaulatyövaihe siirtyy tuotantoketjussa seuraavaan vaiheeseen. Tämän huomioiminen investointipäätöksissä on oleellista tasaisesti virtaavan tuotannon aikaansaamiseksi.