11 resultados para all-ceramic

em Helda - Digital Repository of University of Helsinki


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Milk microfiltration (0.05-0.2 um) is a membrane separation technique which divides milk components into casein-enriched and native whey fractions. Hitherto the effect of intensive microfiltration including a diafiltration step for both cheese and whey processing has not been studied. The microfiltration performance of skimmed milk was studied with polymeric and ceramic MF membranes. The changes caused by decreased concentration of milk lactose, whey protein and ash content for cheese milk quality and ripening were studied. The effects of cheese milk modification on the milk coagulation properties, cheese recovery yield, cheese composition, ripening and sensory quality as well as on the whey recovery yield and composition by microfiltration were studied. The functional properties of whey protein concentrate from native whey were studied and the detailed composition of whey protein concentrate powders made from cheese wheys after cheese milk pretreatments such as high temperature heat treatment (HH), microfiltration (MF) and ultrafiltration (UF) were compared. The studied polymeric spiral wound microfiltration membranes had 38.5% lower energy consumption, 30.1% higher retention of whey proteins to milk retentate and 81.9% lower permeate flux values compared to ceramic membranes. All studied microfiltration membranes were able to separate main whey proteins from skimmed milk. The optimal lactose content of Emmental cheese milk exceeded 3.2% and reduction of whey proteins and ash content of cheese milk with high concentration factor (CF) values increased the rate of cheese ripening. Reduction of whey protein content in cheese milk increased the concentration of caseinomacropeptide (CMP) of total proteins in cheese whey. Reduction of milk whey protein, lactose and ash content reduces milk rennet clotting time and increased the firmness of the coagulum. Cheese yield calculated from raw milk to cheese was lower with microfiltrated milks due to native whey production. Amounts of a-lactalbumin (a-LA) and b-lactoglobulin (b-LG) were significantly higher in the reference whey, indicating that HH, MF and UF milk pretreatments decrease the amounts of these valuable whey proteins in whey. Even low CF values in milk microfiltration (CF 1.4) reduced nutritional value of cheese whey. From the point of view of utilization of milk components it would be beneficial if the amount of native whey and the CMP content of cheese whey could be maximized. Whey protein concentrate powders made of native whey had excellent functional properties and their detailed amino acid composition differed from those of cheese whey protein concentrate powders.

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In Finland, the suicide mortality trend has been decreasing during the last decade and a half, yet suicide was the fourth most common cause of death among both Finnish men and women aged 15 64 years in 2006. However, suicide does not occur equally among population sub-groups. Two notable social factors that position people at different risk of suicide are socioeconomic and employment status: those with low education, employed in manual occupations, having low income and those who are unemployed have been found to have an elevated suicide risk. The purpose of this study was to provide a systematic analysis of these social differences in suicide mortality in Finland. Besides studying socioeconomic trends and differences in suicide according to age and sex, different indicators for socioeconomic status were used simultaneously, taking account of their pathways and mutual associations while also paying attention to confounding and mediatory effects of living arrangements and employment status. Register data obtained from Statistics Finland were used in this study. In some analyses suicides were divided into two groups according to contributory causes of death: the first group consisted of suicide deaths that had alcohol intoxication as one of the contributory causes, and the other group is comprised of all other suicide deaths. Methods included Poisson and Cox regression models. Despite the decrease in suicide mortality trend, social differences still exist. Low occupation-based social class proved to be an important determinant of suicide risk among both men and women, but the strong independent effect of education on alcohol-associated suicide indicates that the roots of these differences are probably established in early adulthood when educational qualifications are obtained and health-behavioural patterns set. High relative suicide mortality among the unemployed during times of economic boom suggests that selective processes may be responsible for some of the employment status differences in suicide. However, long-term unemployment seems to have causal effects on suicide, which, especially among men, partly stem from low income. In conclusion, the results in this study suggest that education, occupation-based social class and employment status have causal effects on suicide risk, but to some extent selection into low education and unemployment are also involved in the explanations for excess suicide mortality among the socially deprived. It is also conceivable that alcohol use is to some extent behind social differences in suicide. In addition to those with low education, manual workers and the unemployed, young people, whose health-related behaviour is still to be adopted, would most probably benefit from suicide prevention programmes.

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In this thesis I examine the U.S. foreign policy discussion that followed the war between Russia and Georgia in August 2008. In the politically charged setting that preceded the presidential elections, the subject of the debate was not only Washington's response to the crisis in the Caucasus but, more generally, the direction of U.S. foreign policy after the presidency of George W. Bush. As of November 2010, the reasons for and consequences of the Russia-Georgia war continue to be contested. My thesis demonstrates that there were already a number of different stories about the conflict immediately after the outbreak of hostilities. I want to argue that among these stories one can discern a “neoconservative narrative” that described the war as a confrontation between the East and the West and considered it as a test for Washington’s global leadership. I draw on the theory of securitization, particularly on a framework introduced by Holger Stritzel. Accordingly, I consider statements about the conflict as “threat texts” and analyze these based on the existing discursive context, the performative force of the threat texts and the positional power of the actors presenting them. My thesis suggests that a notion of narrativity can complement Stritzel’s securitization framework and take it further. Threat texts are established as narratives by attaching causal connections, meaning and actorship to the discourse. By focusing on this process I want to shed light on the relationship between the text and the context, capture the time dimension of a speech act articulation and help to explain how some interpretations of the conflict are privileged and others marginalized. I develop the theoretical discussion through an empirical analysis of the neoconservative narrative. Drawing on Stritzel’s framework, I argue that the internal logic of the narrative which was presented as self-evident can be analyzed in its historicity. Asking what was perceived to be at stake in the conflict, how the narrative was formed and what purposes it served also reveals the possibility for alternative explanations. My main source material consists of transcripts of think tank seminars organized in Washington, D.C. in August 2008. In addition, I resort to the foreign policy discussion in the mainstream media.

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"We report on a search for the standard-model Higgs boson in pp collisions at s=1.96 TeV using an integrated luminosity of 2.0 fb(-1). We look for production of the Higgs boson decaying to a pair of bottom quarks in association with a vector boson V (W or Z) decaying to quarks, resulting in a four-jet final state. Two of the jets are required to have secondary vertices consistent with B-hadron decays. We set the first 95% confidence level upper limit on the VH production cross section with V(-> qq/qq('))H(-> bb) decay for Higgs boson masses of 100-150 GeV/c(2) using data from run II at the Fermilab Tevatron. For m(H)=120 GeV/c(2), we exclude cross sections larger than 38 times the standard-model prediction."

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We present a measurement of the top quark mass and of the top-antitop pair production cross section using p-pbar data collected with the CDFII detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb-1. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 +- 2.4(stat+JES) ^{+1.2}_{-1.0}(syst) GeV/c^2, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure measures also the amount of signal from which we derive a cross section, sigma_{ttbar} = 7.2 +- 0.5(stat) +- 1.0 (syst) +- 0.4 (lum) pb, for the measured values of top quark mass and JES.

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"We report on a search for the standard-model Higgs boson in pp collisions at s=1.96 TeV using an integrated luminosity of 2.0 fb(-1). We look for production of the Higgs boson decaying to a pair of bottom quarks in association with a vector boson V (W or Z) decaying to quarks, resulting in a four-jet final state. Two of the jets are required to have secondary vertices consistent with B-hadron decays. We set the first 95% confidence level upper limit on the VH production cross section with V(-> qq/qq('))H(-> bb) decay for Higgs boson masses of 100-150 GeV/c(2) using data from run II at the Fermilab Tevatron. For m(H)=120 GeV/c(2), we exclude cross sections larger than 38 times the standard-model prediction."

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We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\bar{q_{2}}q_{3}\bar{q_{4}}$) using 943 pb$^{-1}$ of \ppbar collisions at $\sqrt {s} = 1.96$ TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix-element (ME) to $\ttbar$ candidate events. We calculate per-event probability densities according to the ME calculation and construct template models of signal and background. The scale of the jet energy is calibrated using additional templates formed with the invariant mass of pairs of jets. These templates form an overall likelihood function that depends on the top quark mass and on the jet energy scale (JES). We estimate both by maximizing this function. Given 72 observed events, we measure a top quark mass of 171.1 $\pm$ 3.7 (stat.+JES) $\pm$ 2.1 (syst.) GeV/$c^{2}$. The combined uncertainty on the top quark mass is 4.3 GeV/$c^{2}$.

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In this thesis I examine the U.S. foreign policy discussion that followed the war between Russia and Georgia in August 2008. In the politically charged setting that preceded the presidential elections, the subject of the debate was not only Washington's response to the crisis in the Caucasus but, more generally, the direction of U.S. foreign policy after the presidency of George W. Bush. As of November 2010, the reasons for and consequences of the Russia-Georgia war continue to be contested. My thesis demonstrates that there were already a number of different stories about the conflict immediately after the outbreak of hostilities. I want to argue that among these stories one can discern a “neoconservative narrative” that described the war as a confrontation between the East and the West and considered it as a test for Washington’s global leadership. I draw on the theory of securitization, particularly on a framework introduced by Holger Stritzel. Accordingly, I consider statements about the conflict as “threat texts” and analyze these based on the existing discursive context, the performative force of the threat texts and the positional power of the actors presenting them. My thesis suggests that a notion of narrativity can complement Stritzel’s securitization framework and take it further. Threat texts are established as narratives by attaching causal connections, meaning and actorship to the discourse. By focusing on this process I want to shed light on the relationship between the text and the context, capture the time dimension of a speech act articulation and help to explain how some interpretations of the conflict are privileged and others marginalized. I develop the theoretical discussion through an empirical analysis of the neoconservative narrative. Drawing on Stritzel’s framework, I argue that the internal logic of the narrative which was presented as self-evident can be analyzed in its historicity. Asking what was perceived to be at stake in the conflict, how the narrative was formed and what purposes it served also reveals the possibility for alternative explanations. My main source material consists of transcripts of think tank seminars organized in Washington, D.C. in August 2008. In addition, I resort to the foreign policy discussion in the mainstream media.

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We report on a search for the production of the Higgs boson decaying to two bottom quarks accompanied by two additional quarks. The data sample used corresponds to an integrated luminosity of approximately 4  fb-1 of pp̅ collisions at √s=1.96  TeV recorded by the CDF II experiment. This search includes twice the integrated luminosity of the previous published result, uses analysis techniques to distinguish jets originating from light flavor quarks and those from gluon radiation, and adds sensitivity to a Higgs boson produced by vector boson fusion. We find no evidence of the Higgs boson and place limits on the Higgs boson production cross section for Higgs boson masses between 100  GeV/c2 and 150  GeV/c2 at the 95% confidence level. For a Higgs boson mass of 120  GeV/c2, the observed (expected) limit is 10.5 (20.0) times the predicted standard model cross section.