Aktinomykeettien ja homeiden esiintyminen verkostovedessä

Valtaosa Suomen talousvesistä täyttää kaikki asetetut normit ja kuluttajat pitävät talousveden laatua hyvänä, mutta myös suomalaisissa talousvesissä esiintyy mikrobiologisia ongelmia. Yksi tällainen ilmiö on verkostovesien haju- ja makuongelmat, jotka aiheutuvat verkostoissa tapahtuvasta mikrobikasvusta. Tässä oleelliset tekijät ovat putkistojen pinnoilla biofilmeillä kasvavat aktinomykeetit ja mikrosienet (homeet ja hiivat). Aiempaa tutkimustietoa asiasta ei juuri ole, joten Kansanterveyslaitos aloitti vuonna 2004 Vesihuoltolaitosten kehittämisrahaston tukemana tutkimuksen, jossa selvitettiin homeiden ja aktinomykeettien esiintymisestä Suomen talousvesiverkostoissa. Tutkimus käynnistettiin valtakunnallisella kyselyllä, johon vastasi 405: vedenottamoa. Näistä n. 10%:lla oli homeisiin/aktinomykeetteihinmahdollisesti liittyviä haju- tai makuongelmia verkostovesissä

Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters

Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

Hard Single Diffraction in pbarp Collisions at root-s = 630 and 1800 GeV

Using the D0 detector, we have studied events produced in proton-antiproton collisions that contain large forward regions with very little energy deposition (``rapidity gaps'') and concurrent jet production at center-of-mass energies of root-s = 630 and 1800 Gev. The fractions of forward and central jet events associated with such rapidity gaps are measured and compared to predictions from Monte Carlo models. For hard diffractive candidate events, we use the calorimeter to extract the fractional momentum loss of the scattered protons.Comment: 11 pages 4 figures. submitted to PR

Optimierungsprozesse

„Optimierung“ ist ein geläufiger Begriff in fast allen Unternehmen: jeder möchte seine Geschäfts- und Produktionsprozesse verbessern oder „optimieren“, um schlagkräftig am Markt und gleichzeitig renditestark zu bleiben. Doch was hat dieses „Optimieren“ der Praxis mit der mathematischen Diziplin „Optimierung“ zu tun? Ist diese Optimierung in der Praxis nicht einfach ein evolutionäres, häufig modellfreies Probieren und Verwerfen? Oder, werden mathematische Optimierungsmodelle in der Praxis genutzt? Die Antwort ist ernüchternd: Optimierungsmodelle der Mathematik werden zwar gerne in Form von einschlägiger Software gekauft, aber selten längere Zeit genutzt. Warum ist dies so? Beim näheren Hinsehen sind es die beiden Fragen „Was ist zulässig?“ und „Was ist gut?“, die in der Praxis häufig schwer präzise zu beantworten sind und den erfolgreichen Einsatz mathematischer Optimierungsmodelle für Verbesserungsprozesse erschweren. Ein zweites Problem ist der Einsatz komplexer und zeitaufwändiger Simulationen im Verein mit mathematischen Optimierungsalgorithmen. Ist mathematische Optimierung deswegen völlig nutzlos in der Praxis? Flexible parametrische Zulässigkeitsmodelle und Zielfunktionen, sowie hierarchische Strukturierungen mit Einsatz von Surrogaten unter Fehlerschätzern helfen, Optimierungsprozesse in der Praxis mit Hilfe mathematischer Methoden in vernünftigen Rechenzeiten zu unterstützen

Association of leprosy with HLA-DR2 in a Southern Brazilian population

The association between HLA specificities and leprosy was investigated in a Southern Brazilian population. One hundred and twenty-one patients and 147 controls were typed for HLA-A, B, Cw, DR and DQ. Patients were subdivided into the following subgroups, according to clinical, histological and immunological criteria: lepromatous (N = 55), tuberculoid (N = 32), dimorphous (N = 20), and indeterminate (N = 14). The frequencies of HLA specificities were compared between the total group of patients and controls, and between the same controls and each subgroup of patients. After correction of the probabilities, deviations were not significant, except for the DR2 specificity, which presented a frequency of 44.2% in the total group of patients and 56.3% in the subgroup of individuals with the tuberculoid form of the disease, compared to 23.3% in the controls. Stratified analysis showed that the increased DR2 frequency in the total group of patients was due to the subgroups with the tuberculoid and dimorphous forms. The relative risk of tuberculoid leprosy for DR2-positive individuals was 4.2, and the etiologic fraction of DR2 was 0.429. In conclusion, a positive association of the DR2 specificity with the tuberculoid form of leprosy, but not with the lepromatous, dimorphous, or indeterminate forms, was demonstrated in this Southern Brazilian populatio

The bb ¯ ¯ bb¯ production cross section and angular correlations in pp ¯ ¯ ¯ pp¯ collisions at s √ s = 1.8 TeV

We present measurements of the bb-bar Image production cross section and angular correlations using the DØ detector at the Fermilab Tevatron pp-bar Collider operating at ?s = 1.8 TeV. The b quark production cross section for |y^b| < 1.0 and pT^b > 6 GeV/c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between b and bbar quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction