Gravitational wave background from Standard Model physics: qualitative features

Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at 0T > 16 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.

Critical point and scale setting in SU(3) plasma: An update

We explore a method developed in statistical physics which has been argued to have exponentially small finite-volume effects, in order to determine the critical temperature Tc of pure SU(3) gauge theory close to the continuum limit. The method allows us to estimate the critical coupling βc of the Wilson action for temporal extents up to Nτ∼20 with ≲0.1% uncertainties. Making use of the scale setting parameters r0 and t0−−√ in the same range of β-values, these results lead to the independent continuum extrapolations Tcr0=0.7457(45) and Tct0−−√=0.2489(14), with the latter originating from a more convincing fit. Inserting a conversion of r0 from literature (unfortunately with much larger errors) yields Tc/ΛMS¯¯¯¯¯=1.24(10).

Standard Model thermodynamics across the electroweak crossover

Even though the Standard Model with a Higgs mass mH = 125GeV possesses no bulk phase transition, its thermodynamics still experiences a "soft point" at temperatures around T = 160GeV, with a deviation from ideal gas thermodynamics. Such a deviation may have an effect on precision computations of weakly interacting dark matter relic abundances if their mass is in the few TeV range, or on leptogenesis scenarios operating in this temperature range. By making use of results from lattice simulations based on a dimensionally reduced effective field theory, we estimate the relevant thermodynamic functions across the crossover. The results are tabulated in a numerical form permitting for their insertion as a background equation of state into cosmological particle production/decoupling codes. We find that Higgs dynamics induces a non-trivial "structure" visible e.g. in the heat capacity, but that in general the largest radiative corrections originate from QCD effects, reducing the energy density by a couple of percent from the free value even at T > 160GeV.

On loop corrections to the dilepton rate

Next-to-leading order analyses of the dilepton production rate from a hot QCD plasma are reviewed. In general, the photon invariant mass is taken to be in the range K2∼(πT)2, permitting thereby for an interpolation between an OPE computation in a hard regime K2≫(πT)2 and an LPM resummed computation in a soft regime 0

Improved determination of sterile neutrino dark matter spectrum

The putative recent indication of an unidentified 3.55 keV X-ray line in certain astrophysical sources is taken as a motivation for an improved theoretical computation of the cosmological abundance of 7.1 keV sterile neutrinos. If the line is interpreted as resulting from the decay of Warm Dark Matter, the mass and mixing angle of the sterile neutrino are known. Our computation then permits for a determination of the lepton asymmetry that is needed for producing the correct abundance via the Shi-Fuller mechanism, as well as for an estimate of the non-equilibrium spectrum of the sterile neutrinos. The latter plays a role in structure formation simulations. Results are presented for different flavour structures of the neutrino Yukawa couplings and for different types of pre-existing lepton asymmetries, accounting properly for the charge neutrality of the plasma and incorporating approximately hadronic contributions.

Nonperturbative estimate of the heavy quark momentum diffusion coefficient

We estimate the momentum diffusion coefficient of a heavy quark within a pure SU(3) plasma at a temperature of about 1.5Tc. Large-scale Monte Carlo simulations on a series of lattices extending up to 1923×48 permit us to carry out a continuum extrapolation of the so-called color-electric imaginary-time correlator. The extrapolated correlator is analyzed with the help of theoretically motivated models for the corresponding spectral function. Evidence for a nonzero transport coefficient is found and, incorporating systematic uncertainties reflecting model assumptions, we obtain κ=(1.8–3.4)T3. This implies that the “drag coefficient,” characterizing the time scale at which heavy quarks adjust to hydrodynamic flow, is η−1D=(1.8–3.4)(Tc/T)2(M/1.5  GeV)  fm/c, where M is the heavy quark kinetic mass. The results apply to bottom and, with somewhat larger systematic uncertainties, to charm quarks.

Activation of p53 in cervical carcinoma cells by small molecules

In over 90% of cervical cancers and cancer-derived cell lines, the p53 tumor suppressor pathway is disrupted by human papillomavirus (HPV). The HPV E6 protein promotes the degradation of p53 and thus inhibits the stabilization and activation of p53 that would normally occur in response to HPV E7 oncogene expression. Restoration of p53 function in these cells by blocking this pathway should promote a selective therapeutic affect. Here we show that treatment with the small molecule nuclear export inhibitor, leptomycin B, and actinomycin D leads to the accumulation of transcriptionally active p53 in the nucleus of HeLa, CaSki, and SiHa cells. Northern blot analyses showed that both actinomycin D and leptomycin B reduced the amount of HPV E6-E7 mRNA whereas combined treatment with the drugs showed almost complete disappearance of the viral mRNA. The combined treatment activated p53-dependant transcription, and increases in both p21WAF1/CIP1 and Hdm2 mRNA were seen. The combined treatment resulted in apoptotic death in the cells, as evidenced by nuclear fragmentation and PARP-cleavage indicative of caspase 3 activity. These effects were greatly reduced by expressing a dominant negative p53 protein. The present study shows that small molecules can reactivate p53 in cervical carcinoma cells, and this reactivation is associated with an extensive biological response, including the induction of the apoptotic death of the cells.

(Table 1) Radiocarbon ages of samples taken from five sites in north-eastern European Russia

Aim: Concepts about patterns and rates of post-glacial tree population migration are changing as a result of the increasing amount of palaeobotanical information being provided by macroscopic plant remains. Here we combine macrofossil, pollen and stomata records from five sites in north-eastern European Russia and summarize the results for the late-glacial-early Holocene transition. The late-glacial-early Holocene transition encompasses the first indications of trees (tree-type Betula, Picea abies, Abies sibirica and Larix sibirica) and subsequent forest development. Considerable time-lags between the first macrobotanical and/or stomata finds of spruce (Picea abies) and the establishment of a closed forest are reconsidered. Location: Pechora basin, north-eastern European Russia. Methods: We used plant macrofossil, stomata, pollen and radiocarbon analyses to reconstruct late-glacial and early Holocene tree establishment and forest development. The data were derived from lake sediment and peat archives. Results: Palaeobotanical data reveal an early Holocene presence (11,500-10,000 cal. yr bp) of arboreal taxa at all five sites. One site presently located in the northernmost taiga zone, shows the presence of spruce and reproducing tree birch during the late-glacial. Given the current view of post-glacial population dynamics and migration rates, it seems likely that the source area of these early tree populations in north-eastern European Russia was not located in southern Europe but that these populations had local origins. Results thus support the emerging view that the first post-glacial population expansions in non-glaciated regions at high latitudes do not reflect migration from the south but were a result of an increase in the size and density of small persisting outlying tree populations. Main conclusions: Results suggest that the area east of the margin of the Scandinavian ice sheet to the Ural Mountains had isolated patches of trees during the late-glacial and early Holocene and that these small populations acted as initial nuclei for population expansion and forest development in the early Holocene.

Vierasvelkapantinsaajan asema konkurssissa

Tutkielmani tarkoituksena on selvittää voimassa olevan oikeuden perusteella, millaiseksi vierasvelkapantinsaajan asema muodostuu velallisen ja pantinantajan konkurssissa. Panttausta koskevaa yleistä lainsäädäntöä on melko vähän, mutta vierasvelkapanttauksen osalta keskeisimmät säännökset ovat kodifioitu lakiin takauksesta ja vierasvelkapanttauksesta. Takauksesta ja vierasvelkapanttauksesta annettu laki ei kuitenkaan sääntele esimerkiksi tehokkaan panttioikeuden perustamista eikä pantin realisointiin liittyviä tilanteita. Soveltamisohjeita näihin tilanteisiin tulee hakea panttausta koskevasta muusta, varsin hajanaisesta lainsäädännöstä. Tutkimuksen tarkoituksena onkin selvittää tämän pohjaltaan hajanaisen lainsäädännön, lainvalmistelutöiden sekä oikeuskirjallisuuden perusteella, minkälaista suojaa vierasvelkapantinsaaja saa konkurssissa ja millä edellytyksin. Selvitän tutkielman alussa vierasvelkapanttauksen tehokkaalle perustamiselle asetettuja edellytyksiä sekä niiden merkitystä konkurssitilanteessa. Tämän jälkeen tutkin panttioikeuden voimassapysymistä konkurssissa sekä pantinsaajalle tähän liittyen asetettuja velvoitteita. Lisäksi tutkin pantinsaajalla olevia realisointioikeuksia ja niiden rajoituksia sekä pantinsaajan mahdollisuuksia suojautua konkurssitakaisinsaannilta. Tutkielmani kannalta tärkeimpiä lähdeteoksia ovat Erkki Havansi: Esinevakuusoikeudet 1992; Risto Koulu: Konkurssioikeus 2009; Jarno Tepora – Janne Kaisto – Esa Hakkola: Esinevakuudet 2009; Sakari Wuolijoki – Mika Hemmo: Pankkioikeus 2013; Jarmo Tuomisto: Saatavan panttaus 2015 sekä Vierasvelkavakuus ja velallisen insolvenssista johtuva takaisinsaantiriski oikeuskäytännön valossa 2004. Vierasvelkapantinsaajalla on edelleen vahva asema sekä päävelallisen että pantinantajan konkurssissa. Vahvan suojan saaminen edellyttää kuitenkin, että panttioikeus on tehokkaasti perustettu noudattaen muun muassa julkivarmistukselle asetettuja vaatimuksia. Lisäksi nykyiset luotonantajan tiedonantovelvollisuutta koskevat säännökset asettavat luotoantajalle velvollisuuksia, joiden laiminlyöminen tarkoittaa luotonantajan saaman panttihyödyn vähenemistä. Edes vuoden 2004 konkurssilakiin otetuilla säännöksillä, joilla heikennettiin pantinsaajan etuoikeuksia entisestä, ei ole ollut merkittäviä negatiivisia vaikutuksia pantinsaajan oikeuksiin konkurssissa. Pantinsaajan tärkeimpiä taloudellisia etuoikeuksia ei ole tarkoituksenmukaista kaventaa. Lähinnä vain menettelyllisiin etuoikeuksiin voidaan lainsäädännöllä puuttua.

Evaluation of the GPS Accuracy of Tablets

Augmented Reality (AR) applications often require knowledge of the user’s position in some global coordinate system in order to draw the augmented content to its correct position on the screen. The most common method for coarse positioning is the Global Positioning System (GPS). One of the advantages of GPS is that GPS receivers can be found in almost every modern mobile device. This research was conducted in order to determine the accuracies of different GPS receivers. The tests included seven consumer-grade tablets, three external GPS modules and one professional-grade GPS receiver. All of the devices were tested with both static and mobile measurements. It was concluded that even the cheaper external GPS receivers were notably more accurate than the GPS receivers of the tested tablets. The absolute accuracy of the tablets is difficult to determine from the test results, since the results vary by a large margin between different measurements. The accuracy of the tested tablets in static measurements were between 0.30 meters and 13.75 meters.