Porlyl oligopeptidase in development

Prolyl oligopeptidase (POP, prolyl endopeptidase, EC 3.4.21.26) is a serine-type peptidase (family S9 of clan SC) hydrolyzing peptides shorter than 30 amino acids. POP has been found in various mammalian and bacterial sources and it is widely distributed throughout different organisms. In human and rat, POP enzyme activity has been detected in most tissues, with the highest activity found mostly in the brain. POP has gained scientific interest as being involved in the hydrolyzis of many bioactive peptides connected with learning and memory functions, and also with neurodegenerative disorders. In drug or lesion induced amnesia models and in aged rodents, POP inhibitors have been able to revert memory loss. POP may have a fuction in IP3 signaling and it may be a possible target of mood stabilizing substances. POP may also have a role in protein trafficking, sorting and secretion. The role of POP during ontogeny has not yet been resolved. POP enzyme activity and expression have shown fluctuation during development. Specially high enzyme activities have been measured in the brain during early development. Reduced neuronal proliferation and differentation in presence of POP inhibitor have been reported. Nuclear POP has been observed in proliferating peripheral tissues and in cell cultures at the early stage of development. Also, POP coding mRNA is abundantly expressed during brain ontogeny and the highest levels of expression are associated with proliferative germinal matrices. This observation indicates a special role for POP in the regulation of neurogenesis during development. For the experimental part, the study was undertaken to investigate the expression and distribution of POP protein and enzymatic activity of POP in developing rat brain (from embryonic day 14 to post natal day 7) using immunohistochemistry, POP enzyme activity measurements and western blot-analysis. The aim was also to find in vivo confirmation of the nuclear colocalization of POP during early brain ontogeny. For immunohistochemistry, cryosections from the brains of the fetuses/rats were made and stained using specific antibody for POP and fluorescent markers for POP and nuclei. The enzyme activity assay was based on the fluorescence of 7- amino-4-methylcoumarin (AMC) generated from the fluorogenic substrate succinyl-glycyl-prolyl-7-amino-4-methylcoumarin (Suc-Gly-Pro-AMC) by POP. The amounts of POP protein and the specifity of POP antibody in rat embryos was confirmed by western blot analysis. We observed that enzymatic activity of POP is highest at embryonic day 18 while the protein amounts reach their peak at birth. POP was widely present throughout the developmental stages from embryonic day 14 to parturition day, although the POP-immunoreactivity varied abundantly. At embryonic days 14 and 18 notably amounts of POP was distributed at proliferative germinal zones. Furthermore, POP was located in the nucleus early in the development but is transferred to cytosol before birth. At P0 and P7 the POP-immunoreactivity was also widely observed, but the amount of POP was notably reduced at P7. POP was present in cytosol and in intercellular space, but no nuclear POP was observed. These findings support the idea of POP being involved in specific brain functions, such as neuronal proliferation and differentation. Our results in vivo confirm the previous cell culture results supporting the role of POP in neurogenesis. Moreover, an inconsistency of POP protein amounts and enzymatic activity late in the development suggests a strong regulation of POP activity and a possible non-hydrolytic role at that stage.

Top Quark Mass Measurement in the lepton+jets Channel Using a Matrix Element Method and in situ Jet Energy Calibration

A precision measurement of the top quark mass m_t is obtained using a sample of ttbar events from ppbar collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m_t and a parameter DJES to calibrate the jet energy scale /in situ/. Using a total of 1087 events, a value of m_t = 173.0 +/- 1.2 GeV/c^2 is measured.

Top quark mass measurement in the lepton plus jets channel using a modified matrix element method

We report a measurement of the top quark mass, m_t, obtained from ppbar collisions at sqrt(s) = 1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb^-1. We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, with effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m_t and a parameter JES that determines /in situ/ the calibration of the jet energies. We use a neural network discriminant to distinguish signal from background events. We also apply a cut on the peak value of each event likelihood curve to reduce the contribution of background and badly reconstructed events. Using the 318 events that pass all selection criteria, we find m_t = 172.7 +/- 1.8 (stat. + JES) +/- 1.2 (syst.) GeV/c^2.

Search for Gluino-Mediated Bottom Squark Production in pp̅ Collisions at √s=1.96 TeV

We report on a search for the supersymmetric partner of the bottom quark produced from gluino decays in data from 2.5 fb-1 of integrated luminosity collected by the Collider Detector at Fermilab at sqrt(s)=1.96 TeV. Candidate events are selected requiring two or more jets and large missing transverse energy. At least two of the jets are required to be tagged as originating from a b quark to enhance the sensitivity. The results are in good agreement with the prediction of the standard model processes, giving no evidence for gluino decay to sbottom quarks. This result constrains the gluino-pair-production cross section to be less than 40fb at 95% credibility level for a gluino mass of 350 GeV.

Measurement of the tt̅ cross section in pp̅ collisions at √s=1.96 TeV using dilepton events with a lepton plus track selection

This paper reports a measurement of the cross section for the pair production of top quarks in ppbar collisions at sqrt(s) = 1.96 TeV at the Fermilab Tevatron. The data was collected from the CDF II detector in a set of runs with a total integrated luminosity of 1.1 fb^{-1}. The cross section is measured in the dilepton channel, the subset of ttbar events in which both top quarks decay through t -> Wb -> l nu b where l = e, mu, or tau. The lepton pair is reconstructed as one identified electron or muon and one isolated track. The use of an isolated track to identify the second lepton increases the ttbar acceptance, particularly for the case in which one W decays as W -> tau nu. The purity of the sample may be further improved at the cost of a reduction in the number of signal events, by requiring an identified b-jet. We present the results of measurements performed with and without the request of an identified b-jet. The former is the first published CDF result for which a b-jet requirement is added to the dilepton selection. In the CDF data there are 129 pretag lepton + track candidate events, of which 69 are tagged. With the tagging information, the sample is divided into tagged and untagged sub-samples, and a combined cross section is calculated by maximizing a likelihood. The result is sigma_{ttbar} = 9.6 +/- 1.2 (stat.) -0.5 +0.6 (sys.) +/- 0.6 (lum.) pb, assuming a branching ratio of BR(W -> ell nu) = 10.8% and a top mass of m_t = 175 GeV/c^2.

Measurements of the top-quark mass using charged particle tracking

We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9+9.5-8.5 (stat) +/- 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5+8.8-8.9 (stat) +/- 3.8 (syst) GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3 (stat) +/- 2.6 (syst) GeV/c2.

Search for new color-octet vector particle decaying to t tbar in p pbar collisions at sqrt{s} = 1.96 TeV

We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb$^{-1}$ of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study $t\bar{t}$ events in the lepton+jets channel with at least one $b$-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV$/c^2$ and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.

Massa- ja paperiteollisuuden supistumisen ja tulevaisuuden kuvien aluetaloudelliset vaikutukset

Tutkimus on jatkoa Ruralia-instituutin syksyllä 2008 julkaisemalle metsäteollisuuden mahdollisen supistumisen aluetaloudellisia vaikutuksia selvittäneelle työlle. Päivitetty tutkimus on edellistä kattavampi, sillä selvitys ulottuu nyt kaikkiin Suomen massa- ja paperiteollisuuden yrityksiin. Massa- ja paperiteollisuuden vuoden 2007 alusta syksyyn 2009 ilmoittamat pysyvät kapasiteetin leikkaukset ovat yhteensä lähes 19,0 % vuoden 2007 tasoon verrattuna. Massan valmistuksessa menetykset ovat yli 20 % ja paperin/kartongin valmistuksessa noin 17 %. Supistamispäätökset merkitsevät kerroinvaikutuksineen yhteensä 1,4 miljardin euron ja 8 800 henkilötyövuoden menetystä. Kun vähennykset suhteutetaan menetyksiä kärsineiden maakuntien yhteenlaskettuun BKT:n ja työllisten määrään, toimenpiteet vastaavat 2,0 % laskua taloudellisessa kasvussa ja 0,8 % menetystä työllisyydessä. Vuoden 2008 lopulla vastaavat menetykset olivat 0,9 miljardia euroa ja 6 000 henkilötyövuotta. Vaikeudet keskittyvät itäiseen Suomeen. Kymenlaakso on kärsinyt suurimmat menetykset rahallisesti ja työllisten määrässä. Suhteellisesti eniten on menettänyt Kainuu. Pohjois-Savo nousee menettäjänä kolmen kärkeen, jos Stora Enson Varkauden tehtaiden sulkeminen toteutuu vuoden 2010 lopussa. Myös Keski-Suomessa, Lapissa ja Pohjanmaalla on suljettu kokonaisia tehtaita ja tästä on tullut selviä vaurioita. Pienemmillä tappioilla ovat selvinneet Etelä-Karjala, Pohjois-Karjala, Pohjois-Pohjanmaa ja Satakunta, joissa on ollut vain tuotannon seisokkeja ja/tai yksittäisiä tuotantolinjojen sulkemisia. Alueet, joiden elinkeinorakenne on monipuolinen, sopeutuvat nopeammin metsäteollisuuden supistumiseen. Tämä näkyy muun muassa pienempinä työllisyysmenetyksinä. Lisäksi aluetalouden koolla on merkitystä. Pienille aluetalouksille vaikutukset ovat voimakkaammat. Tutkimuksessa tarkasteltiin myös metsäteollisuuden rakennemuutoksen etenemisen vaikutuksia. Jos kehitys jatkuu negatiivisena, kuten Metla esitti keväällä 2009 tai pelätty kauhuskenaario alan tuotannon puoliintumisesta toteutuisi, kansantalouden menetykset olisivat merkittävät. Metlan skenaariossa BKT:n vähentyminen olisi kumulatiivisesti laskettuna suurimmillaan vuosien 2009 ja 2013 aikana, noin 450 miljoonaa euroa. Vastaavasti kauhuskenaariossa summa olisi lähes 700 miljoonaa euroa. Menetystä korostaa talouslama, minkä vuoksi muut alat eivät pysty täysin kompensoimaan massa- ja paperiteollisuuden vaikeuksia. Kokonaistuotanto näyttäisi kuitenkin toipuvan, mikäli nykyinen lama jäisi lyhyeksi. Työllisyys kärsisi huomattavasti kummassakin negatiivisessa skenaariossa. Vastapainoksi tutkittiin myös ns. sisäisen devalvaation sekä paperimarkkinoiden elpymisen vaikutusta. Sisäinen devalvaatio toteutuisi massa- ja paperiteollisuuden maltillisen palkkaratkaisun ja Ruotsin kruunun devalvoitumista vastaavan kustannusedun kautta. Kansainvälisten paperimarkkinoiden elpymisen vaikutusta tutkittiin vientihintoja ja -määriä nostamalla. Näistä tehokkaimmaksi osoittautui vientihintojen nousu. Myönteisten skenaarioiden vaikutusten ja nykyisten päätösten aiheuttamien aluetaloudellisten menetysten vertaaminen kuitenkin paljastaa, että vieläkin parempaa kehitystä vaaditaan. Kymenlaakso ja Pohjois-Savo jäisivät edelleen miinukselle.