97 research outputs found

    Thrips (Thysanoptera) from dead aspen (Populus tremula) trees in Eastern Finland

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    Thrips were collected from dead aspens (Populus tremula) using trunk-window traps at two forest areas in Eastern Finland during 2001 and 2002.We collected 156 individuals of 23 species (15 Terebrantia; 8 Tubulifera). Four of the species – all Tubulifera – were previously unknown from Finland, and two unknown from Fennoscandia, indicating that the thrips fauna of this area is poorly known. Three of these species, Hoplothrips carpathicus Pelikán, Liophloeothrips glaber Priesner and L. hungaricus (Priesner) are fungivores, while Lispothrips crassipes (Jablonowski) is an arboreal herbivore. The species assemblages of the study areas are compared and a list presented of all species collected

    Using age difference and sex similarity to detect evidence of sibling influence on criminal offending

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    Background Sibling resemblance in crime may be due to genetic relatedness, shared environment, and/or the interpersonal influence of siblings on each other. This latter process can be understood as a type of 'peer effect' in that it is based on social learning between individuals occupying the same status in the social system (family). Building on prior research, we hypothesized that sibling pairs that resemble peer relationships the most, i.e., same-sex siblings close in age, exhibit the most sibling resemblance in crime. Methods Drawing on administrative microdata covering Finnish children born in 1985-97, we examined 213 911 sibling pairs, observing the recorded criminality of each sibling between ages 11 and 20. We estimated multivariate regression models controlling for individual and family characteristics, and employed fixed-effects models to analyze the temporal co-occurrence of sibling delinquency. Results Among younger siblings with a criminal older sibling, the adjusted prevalence estimates of criminal offending decreased from 32 to 25% as the age differences increased from less than 13 months to 25-28 months. The prevalence leveled off at 23% when age difference reached 37-40 months or more. These effects were statistically significant only among same-sex sibling pairs (p < 0.001), with clear evidence of contemporaneous offending among siblings with minimal age difference. Conclusions Same-sex siblings very close in age stand out as having the highest sibling resemblance in crime. This finding suggests that a meaningful share of sibling similarity in criminal offending is due to a process akin to peer influence, typically flowing from the older to the younger sibling.Peer reviewe

    Yritysten työeläkemaksut vuonna 2003

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    Julkaisu sisältää tilastotietoja yritysten maksamista lopullisista vakuutusmaksuista vuonna 2003. Tiedot perustuvat eläkevakuutusyhtiöiltä saatuihin vakuutuskohtaisiin tietoihin ja eläkesäätiöiden ja -kassojen työnantajakohtaisiin tilinpäätöstietoihin ja eläkkeiden kustannusten perusteena oleviin tietoihin

    Ray optics for absorbing particles with application to ice crystals at near-infrared wavelengths

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    Light scattering by particles large compared to the wavelength of incident light is traditionally solved using ray optics which considers absorption inside the particle approximately, along the ray paths. To study the effects rising from this simplification, we have updated the ray-optics code SIRIS to take into account the propagation of light as inhomogeneous plane waves inside an absorbing particle. We investigate the impact of this correction on traditional ray-optics computations in the example case of light scattering by ice crystals through the extended near-infrared (NIR) wavelength regime. In this spectral range, ice changes from nearly transparent to opaque, and therefore provides an interesting test case with direct connection and applicability to atmospheric remote-sensing measurements at NIR wavelengths. We find that the correction for inhomogeneous waves systematically increases the single-scattering albedo throughout the NIR spectrum for both randomly-oriented, column-like hexagonal crystals and ice crystals shaped like Gaussian random spheres. The largest increase in the single-scattering albedo is 0.042 for hexagonal crystals and 0.044 for Gaussian random spheres, both at λ=2.725 µm. Although the effects on the 4  ×  4 scattering-matrix elements are generally small, the largest differences are seen at 2.0 µm and 3.969 µm wavelengths where the correction for inhomogeneous waves affects mostly the backscattering hemisphere of the depolarization-connected P22/P11, P33/P11, and P44/P11. We evaluated the correction for inhomogeneous waves through comparisons against the discrete exterior calculus (DEC) method. We computed scattering by hexagonal ice crystals using the DEC, a traditional ray-optics code (SIRIS3), and a ray-optics code with inhomogeneous waves (SIRIS4). Comparisons of the scattering-matrix elements from SIRIS3 and SIRIS4 against those from the DEC suggest that consideration of the inhomogeneous waves brings the ray-optics solution generally closer to the exact result and, therefore, should be taken into account in scattering by absorbing particles large compared to the wavelength of incident light.Peer reviewe
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