Mafisten ja ultramafisten vulkaniittien petrologia Kittilän alueella

Tiivistelmä. Kittilän vihreäkivikompleksina tunnettu Kittilän sviitti on Keski-Lapin vihreäkivivyöhykkeeseen kuuluvista vulkaanissyntyisistä yksiköistä nuorin (n. 2015 Ma). Kittilän sviitti on jopa 9 kilometrin paksuinen tholeiittinen vulkaniittikerrostuma, joka on syntynyt mantereiden repeämisen aikana muodostuneeseen juveliiniin merenpohjaan ja se on ainakin osittain alloktoninen. Runsaiden metavulkaniittien lisäksi sviitissä on myös merellisiin sedimenttialtaisiin kerrostuneita kemiallisia sedimenttejä sekä vulkaniittien päälle kerrostuneita, nuorempia sedimenttisisiä kvartsi-maasälpäliuskeita. Kittilän sviitin kivilajit voidaan jakaa neljään eri muodostumaan, jotka ovat Kautoselän, Porkosen, Vesmajärven ja Pyhäjärven muodostumat. Tämän opinnäytetyön tavoitteena oli perehtyä erityisesti vulkaanissyntyisten Kautoselän ja Vesmajärven muodostumien ja niihin kuuluvien vulkaniittien petrologiaan. Tutkimusalueelta, joka oli laajuudeltaan noin 1220 km² ja ulottui 30 kilometrin etäisyydelle Kittilän kultakaivoksesta (Suurikuusikko), kerättiin kalliopaljastumista ja kairasydämistä 128 näytettä, joille tehtiin kokokivianalyysi XRF-menetelmällä. Näiden analyysien perusteella valittiin 95 näytettä, joille tehtiin tarkempi REE- ja hivenalkuaineiden määritys ICP-MS- ja ICP-OES menetelmillä. Tutkimusalueen kivilajien petrografista kuvausta varten teetettiin 49 kiillotettua ohuthiettä. Geokemiallisten analyysien perusteella tutkimusalueella esiintyy kaksi vallitsevaa ja toisistaan selkeästi erottuvaa vulkaniittiyksikköä, jotka voidaan luokitella aiempien tutkimuksten yhteydessä määritettyihin Kautoselän ja Vesmajärven muodostumiin. Kautoselän muodostuman vulkaniitit erottuvat Vesmajärven muodostumasta niiden huomattavasti jyrkemmän kondriittinormalisoidun REE-jakauman ja jopa kolmikertaisilla pääalkuaineiden K, Ti ja P ja hivenalkuaineiden Zr, Ce, Eu, Gd, La, Nd, Pr, Rb, Sm, Tb, Ba ja Be pitoisuuksilla. Vesmajärven muodostumaan rinnastettujen vulkaniittien REE-jakauma on lähes tasainen ja vain Cr-, Mg- ja Ni-pitoisuudet ovat Kautoselän muodostumaa korkeammat. Yksinomaan Fe-tholeiittisita basalteista koostuva Kautoselän muodostuma vastaa koostumukseltaan mantereisia basaltteja, kun taas Vesmajärven muodostumaan rinnastetut Fe- ja Mg-tholeiittiset basaltit vastaavat valtameren keskiselänteen basaltteja, mikä viittaa niiden syntyneen vaikutuksessa merelliseen litosfäärilaattaan tai mantereiden repeämisen yhteydessä. Edellä mainittuihin muodostumiin luokiteltujen vulkaniittien koostumuksilla ei ole selkeää rajaa. Tutkimusalueella esiintyy satunnainen, muutamista näytteistä koostuva joukko, joka koostumukseltaan soveltuu luokiteltavaksi kumpaankin muodostumaan. Vesmajärven ja Kautoselän muodostumaan luokiteltujen vulkaniittien lisäksi tutkimusalueella esiintyy myös kehittyneempiä, Könkään muodostumalle tyypillisiä basaltteja sekä koostumukseltaan komatiittisia basaltteja ja ultraemäksisiä oliviinikumulaatteja. Kehittyneet basaltit eroavat Vesmajärven ja Kautoselän muodostumaan rinnastetuista basalteista niiden erittäin korkeiden Zr-, P- ja Ti-pitoisuuksien puolesta. Koostumukseltaan pikriittejä tai Ti-rikastuneita komatiitteja vastaavat ultraemäksiset laavat ovat voimakkaasti muuttuneita ja vain kromiitti on säilynyt niissä lähes primäärinä. Kromiitteihin tehtyjen mikroanalyysien perusteella niiden koostumukset vastaavat osittain Kittilän alueella sijaitsevien Peuranmaan pikriittien sekä Jeesiörovan komatiitteja. Ultraemäksisten laavojen kondriittinormalisoitu REE-jakauma ei kuitenkaan vastaa Keski-Lapin muita, LREE-alkuaineista köyhtyneitä komatiitteja, vaan se on selkeästi LREE-rikastunut ja muistuttaa läheisesti Savukosken ryhmään kuuluvia pikriittejä

Use of Gas Electron Multiplier (GEM) Detectors for an Advanced X-ray Monitor

We describe a concept for a NASA SMEX Mission in which Gas Electron Multiplier (GEM) detectors, developed at CERN, are adapted for use in X-ray astronomy. These detectors can be used to obtain moderately large detector area and two-dimensional photon positions with sub mm accuracy in the range of 1.5 to 15 keV. We describe an application of GEMs with xenon gas, coded mask cameras, and simple circuits for measuring event positions and for anticoincidence rejection of particle events. The cameras are arranged to cover most of the celestial sphere, providing high sensitivity and throughput for a wide variety of cosmic explosions. At longer timescales, persistent X-ray sources would be monitored with unprecedented levels of coverage. The sensitivity to faint X-ray sources on a one-day timescale would be improved by a factor of 6 over the capability of the RXTE All Sky Monitor.Comment: 10 pages, 5 figs., in X-Ray and Gamma Ray Instrumentation for Astronomy XI, SPIE conference, San Diego, Aug. 200

Large maternal waist circumference in relation to height is associated with high glucose concentrations in an early-pregnancy oral glucose tolerance test : A population-based study

Publisher Copyright: © 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).Introduction: To explore the role of maternal anthropometric characteristics in early-pregnancy glycemia, we analyzed the associations and interactions of maternal early-pregnancy waist circumference (WC), height and pre-pregnancy body mass index (BMI) with plasma glucose concentrations in an oral glucose tolerance test (OGTT) at 12–16 weeks’ gestation. Material and Methods: A population-based cohort of 1361 pregnant women was recruited in South Karelia, Finland, from March 2013 to December 2016. All participants had their WC, weight, height, HbA1c, and blood pressure measured at 8–14 weeks’ gestation and subsequently underwent a 2-h 75-g OGTT, including assessment of fasting insulin concentrations, at 12–16 weeks’ gestation. BMI (kg/m2) was calculated using self-reported pre-pregnancy weight. Maternal WC ≥80 cm was defined as large. Maternal height ≥166 cm was defined as tall. Data on gestational diabetes treatment was extracted from hospital records. Results: In the total cohort, 901 (66%) of women had an early-pregnancy WC ≥80 cm, which was associated with higher early-pregnancy HbA1c, higher concentrations of fasting plasma glucose and serum insulin, higher post-load plasma glucose concentrations, higher HOMA-IR indices, higher blood pressure levels, and higher frequencies of pharmacologically treated gestational diabetes, than early-pregnancy WC 0.5 was positively associated with both fasting and post-load plasma glucose concentrations at 12–16 weeks’ gestation, even when adjusted for age, smoking, nulliparity, and family history of type 2 diabetes. The best cut-offs for WHtR (0.58 for 1-h plasma glucose, and 0.54 for 2-h plasma glucose) were better predictors of post-load glucose concentrations >90th percentile than the best cut-offs for BMI (28.1 kg/m2 for 1-h plasma glucose, and 26.6 kg/m2 for 2-h plasma glucose), with areas-under-the-curve (95% confidence interval) 0.73 (0.68–0.79) and 0.73 (0.69–0.77), respectively, for WHtR, and 0.68 (0.63–0.74) and 0.69 (0.65–0.74), respectively, for BMI. Conclusions: In our population-based cohort, early-pregnancy WHtR >0.5 was positively associated with both fasting and post-load glucose concentrations at 12–16 weeks’ gestation and performed better than BMI in the prediction of post-load glucose concentrations >90th percentile. Overall, our results underline the importance of evaluating maternal abdominal adiposity in gestational diabetes risk assessment.Peer reviewe

Search for the ac Josephson effect in superfluid 3He

Experiments testing for the existence of the ac Josephson effect in superfluid 3He, analogous to phenomena observed in superconducting microbridges, have been performed. Small holes were employed as the weak link between two reservoirs filled with 3He; several different orifice geometries were tried. Simple model calculations suggest that steps in the flow characteristics should be observable with our resolution when an ac pressure modulation is applied across the weak link. We found that such effects do not exist for the parameter values used in our experiments.Peer reviewe

Cortical beta burst dynamics are altered in Parkinson's disease but normalized by deep brain stimulation

Exaggerated subthalamic beta oscillatory activity and increased beta range cortico-subthalamic synchrony have crystallized as the electrophysiological hallmarks of Parkinson's disease. Beta oscillatory activity is not tonic but occurs in 'bursts' of transient amplitude increases. In Parkinson's disease, the characteristics of these bursts are altered especially in the basal ganglia. However, beta oscillatory dynamics at the cortical level and how they compare with healthy brain activity is less well studied. We used magnetoencephalography (MEG) to study sensorimotor cortical beta bursting and its modulation by subthalamic deep brain stimulation in Parkinson's disease patients and age-matched healthy controls. We show that the changes in beta bursting amplitude and duration typical of Parkinson's disease can also be observed in the sensorimotor cortex, and that they are modulated by chronic subthalamic deep brain stimulation, which, in turn, is reflected in improved motor function at the behavioural level. In addition to the changes in individual beta bursts, their timing relative to each other was altered in patients compared to controls: bursts were more clustered in untreated Parkinson's disease, occurring in 'bursts of bursts', and re-burst probability was higher for longer compared to shorter bursts. During active deep brain stimulation, the beta bursting in patients resembled healthy controls' data. In summary, both individual bursts' characteristics and burst patterning are affected in Parkinson's disease, and subthalamic deep brain stimulation normalizes some of these changes to resemble healthy controls' beta bursting activity, suggesting a non-invasive biomarker for patient and treatment follow-up.Peer reviewe

Search for the ac Josephson effect in superfluid He3

Experiments testing for the existence of the ac Josephson effect in superfluid He3, analogous to phenomena observed in superconducting microbridges, have been performed. Small holes were employed as the weak link between two reservoirs filled with He3; several different orifice geometries were tried. Simple model calculations suggest that steps in the flow characteristics should be observable with our resolution when an ac pressure modulation is applied across the weak link. We found that such effects do not exist for the parameter values used in our experiments. © 1983 The American Physical Society

Models of multivariate regression for labor accidents in different production sectors: comparative study

The present article shows the results of an investigation carried out on the use of alternatives to carry out work accident studies in an objective manner in three production sectors that are of high risk: the electric power production sector, cement production and oil refining sector, so the main objective is focused on identifying the influential variables and the regression model that best explains the accident in each of these sectors and perform a comparative analysis between them. Among the techniques and tools used (data mining) are those related to multivariate statistics and generalized linear models and through the Akaike information criterion and Bayeciano criterion, it was possible to determine that the best regression model that explains the accident rate in two of the sectors studied is the negative binomial (cement and petroleum refining), while in the electric power sector, the best fit model resulted in Logistic Regression. In turn, for the three sectors in general, the variables that have the most significant impact are related to aspects such as: management commitment, occupational safety climate, safety training, psychosocial aspects and ergonomic sources, this result was corroborated by means of an accident analysis carried out in these three sectors

Solar Intensity X-Ray and Particle Spectrometer SIXS : Instrument Design and First Results

The Solar Intensity X-ray and particle Spectrometer (SIXS) on the BepiColombo Mercury Planetary Orbiter ("Bepi") measures the direct solar X-rays, energetic protons, and electrons that bombard, and interact with, the Hermean surface. The interactions result in X-ray fluorescence and scattering, and particle induced X-ray emission (PIXE), i.e. "glow" of the surface in X-rays. Simultaneous monitoring of the incident and emitted radiation enables derivation of the abundances of some chemical elements and scattering properties of the outermost surface layer of the planet, and it may reveal other sources of X-ray emission, due to, for example, weak aurora-like phenomena in Mercury's exosphere. Mapping of the Hermean X-ray emission is the main task of the MIXS instrument onboard BepiColombo. SIXS data will also be used for investigations of the solar X-ray corona and solar energetic particles (SEP), both in the cruise phase and the passes of the Earth, Venus and Mercury before the arrival at Mercury's orbit, and the final science phase at Mercury's orbit. These observations provide the first-ever opportunity for in-situ measurements of the propagation of SEPs, their interactions with the interplanetary magnetic field, and space weather phenomena in multiple locations throughout the inner solar system far away from the Earth, and more extensively at Mercury's orbit. In this paper we describe the scientific objectives, design and calibrations, operational principles, and scientific performance of the final SIXS instrument launched to the mission to planet Mercury onboard BepiColombo. We also provide the first analysis results of science observations with SIXS, that were made during the Near-Earth Commissioning Phase and early cruise phase operations in 2018-19, including the background X-ray sky observations and "first light" observations of the Sun with the SIXS X-ray detection system (SIXS-X), and in-situ energetic electron and proton observations with the SIXS Particle detection system (SIXS-P).Peer reviewe