Precision Determination of ∣Vub∣|V_{ub}|

The last two years have seen an impressive improvement in the determination of $|V_{ub}|$, especially from inclusive decays. The error on $|V_{ub}|$ measured with inclusive decays was reduced from 18% (PDG 2004) to 8% (PDG 2006). This progress is a result of combined experimental and theoretical efforts. In this talk, the theoretical framework (BLNP) that enabled such progress is reviewed, as well as other approaches to an inclusive determination of $|V_{ub}|$ (DGE, $M_X-q^2$ etc.). The prospects of improving $|V_{ub}|$ are discussed, addressing issues of weak annihilation, implications of leptonic B decays, and determination of $|V_{ub}|$ with exclusive decays.Comment: Invited talk at International Conference on B-Physics at Hadron Machines (Beauty 2006), Oxford, England, 25-29 Sep 200

Girls' and boys' understanding of their class environment and their well-being in physical education in high school

Masteroppgave - Lektor i kroppsøving og idrettsfag - 202

Counter-Urban Activity out of Copenhagen: Who, Where and Why?

While migration is often understood as movement towards cities, it can also assume another direction, traditionally termed counter-urbanisation. This paper contributes to the study of counter-urbanisation by investigating data on settlement patterns to places outside commuting distance to the Copenhagen labour market. Counter-urban migration outside of the Copenhagen commuting area is compared with out-migration from Copenhagen to suburbs and commuting areas in the period from 2005 to 2020, reflecting periods of both economic growth and recession. In this paper, we explore this development in terms of the numbers and characteristics of migrants moving out of commuting distance in comparison to those migrants who leave the city to settle in the suburbs or within commuting distance. The quantitative findings are combined with qualitative findings from a survey of the motives of migrants. In line with earlier studies, this study finds that family, friends, place-specific relations and job opportunities are important motives for moving. However, the results also show that an increasing share of migrants have higher education. This will contribute to the future economic and social sustainability of rural and peripheral places in Denmark

A shared-parameter continuous-time hidden Markov and survival model for longitudinal data with informative dropout

A shared-parameter approach for jointly modeling longitudinal and survival data is proposed. With respect to available approaches, it allows for time-varying random effects that affect both the longitudinal and the survival processes. The distribution of these random effects is modeled according to a continuous-time hidden Markov chain so that transitions may occur at any time point. For maximum likelihood estimation, we propose an algorithm based on a discretization of time until censoring in an arbitrary number of time windows. The observed information matrix is used to obtain standard errors. We illustrate the approach by simulation, even with respect to the effect of the number of time windows on the precision of the estimates, and by an application to data about patients suffering from mildly dilated cardiomyopathy

DA FORMAÇÃO DO RESERVATÓRIO À CRIAÇÃO DA PLATAFORMA DE ENERGIAS RENOVÁVEIS: 40 ANOS DE ESTRATÉGIAS AMBIENTAIS DA HIDRELÉTRICA BINACIONAL DE ITAIPU

Concebido como um empreendimento para a geração de energia elétrica no rio Paraná, a construção da Itaipu Binacional deu-se durante os governos militares do Brasil e do Paraguai, na década de 1970. O fechamento das comportas do canal de desvio, em 1982, gerou o grande lago de Itaipu, com 1.350 km² de extensão, causando enormes impactos ao meio físico, biótico e antrópico, alterando a geografia do oeste do Paraná e inundando grandes porções de matas nativas no território paraguaio. Ao longo desses 40 anos de existência, é possível contextualizar as estratégias ambientais desta empresa, identificando quatro fases distintas. O presente artigo descreve essas fases, que tiveram início em 1975 e se atualizam na recente criação da Plataforma Itaipu de Energias Renováveis, em 2008, que se destaca por desenvolver projetos de estímulo ao emprego de fontes de energias renováveis - solar, eólica, de biomassa e hidráulica. Hoje, a Plataforma e o Centro Internacional de Hidroinformática (CIH) são apoiados por uma cátedra da UNESCO sobre o Nexo Água e Energia no Programa de Pós Graduação em Meio Ambiente e Desenvolvimento da Universidade Federal do Paraná

High sensitivity measurement of 224Ra and 226Ra in water with an improved hydrous titanium oxide technique at the Sudbury Neutrino Observatory

The existing hydrous titanium oxide (HTiO) technique for the measurement of 224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been changed to make it faster and less sensitive to trace impurities in the HTiO eluate. Using HTiO-loaded filters followed by cation exchange adsorption and HTiO co-precipitation, Ra isotopes from 200-450 tonnes of heavy water can be extracted and concentrated into a single sample of a few millilitres with a total chemical efficiency of 50%. Combined with beta-alpha coincidence counting, this method is capable of measuring 2.0x10^3 uBq/kg of 224Ra and 3.7x10^3 uBq/kg of 226Ra from the 232Th and 238U decay chains, respectively, for a 275 tonne D2O assay, which are equivalent to 5x10^16 g Th/g and 3x10^16 g U/g in heavy water.Comment: 8 Pages, 2 figures and 2 table

Architecture of the type IVa pilus machine

Many bacteria, including important pathogens, move by projecting grappling-hook–like extensions called type IV pili from their cell bodies. After these pili attach to other cells or objects in their environment, the bacteria retract the pili to pull themselves forward. Chang et al. used electron cryotomography of intact cells to image the protein machines that extend and retract the pili, revealing where each protein component resides. Putting the known structures of the individual proteins in place like pieces of a three-dimensional puzzle revealed insights into how the machine works, including evidence that ATP hydrolysis by cytoplasmic motors rotates a membrane-embedded adaptor that slips pilin subunits back and forth from the membrane onto the pilus

Centrosomes : methods for preparation

The centrosome of higher eukaryotic cells is the main microtubule-organising centre. To understand the molecular mechanisms underlying this organelle's biogenesis and important functions in several cellular processes, such as microtubule nucleation, cell division and stress response, it was critical to develop methods for isolating biochemically meaningful quantities of centrosomes. Centrosomes have been isolated from a variety of organisms and based on these preparations, numerous aspects of this intriguing organelle's morphological, functional and biochemical properties have been uncovered. Better isolation procedures along with the development of new technologies, like RNAi (ribonucleic acid interference) and the increasing accuracy of mass spectrometry and electron microscopy techniques, have profoundly improved our knowledge of the centrosome, leading to a better understanding of its implications in various cellular processes and in diseases

SKI2 mediates degradation of RISC 5'-cleavage fragments and prevents secondary siRNA production from miRNA targets in <i>Arabidopsis</i>

Small regulatory RNAs are fundamental in eukaryotic and prokaryotic gene regulation. In plants, an important element of post-transcriptional control is effected by 20–24 nt microRNAs (miRNAs) and short interfering RNAs (siRNAs) bound to the ARGONAUTE1 (AGO1) protein in an RNA induced silencing complex (RISC). AGO1 may cleave target mRNAs with small RNA complementarity, but the fate of the resulting cleavage fragments remains incompletely understood. Here, we show that SKI2, SKI3 and SKI8, subunits of a cytoplasmic cofactor of the RNA exosome, are required for degradation of RISC 5′, but not 3′-cleavage fragments in Arabidopsis. In the absence of SKI2 activity, many miRNA targets produce siRNAs via the RNA-dependent RNA polymerase 6 (RDR6) pathway. These siRNAs are low-abundant, and map close to the cleavage site. In most cases, siRNAs were produced 5′ to the cleavage site, but several examples of 3′-spreading were also identified. These observations suggest that siRNAs do not simply derive from RDR6 action on stable 5′-cleavage fragments and hence that SKI2 has a direct role in limiting secondary siRNA production in addition to its function in mediating degradation of 5′-cleavage fragments